SERVICE MANUAL UPDATE STEERING WHEEL CONTROLS

Models Affected: 1989 BONNEVILLE, GRAND PRIX AND 6000 MODELS

The attached Service Manual information for Sections 3F and 8A were not available when the 1989 Pontiac Bonneville Service Manual was shipped to dealerships.

Items of special concern are use of steering wheel removal tool J 1859-03 and bulb replacement. The removal tool bolts must be installed to not more than 5 full turns to prevent damage to the steering wheel control components in the column. Bulb replacement can be done only at Delco repair shops. The vehicle can still be driven, and the horns are not affected by control button assembly removal. Although the 6000 and Grand Prix models have several different functions (see Figure 2) on their control button assemblies, service procedures for the Bonneville assembly are still applicable.

SECTION 3F STEERING WHEEL CONTROLS ----------------------- NOTICE: When fasteners are removed, always reinstall them at the same location from which they were removed. If a fastener needs to be replaced, use the correct part number for that application. If the correct part number fastener is not available, a fastener of equal size and strength (or stronger) may be used. Fasteners that are not reused, and those requiring thread locking compound will be called out. The correct torque value must be used when installing fasteners that require it. If the above conditions are not followed, parts or system damage could result.

CONTENTS

CONTROLS SYSTEM COMPONENTS Steering Wheel Controls System 3F-1 Control Button Functions 3F-2 UNIT REPAIR Control Buttons Assembly 3F-2 Bulb Service 3F-2 Horn Pad 3F-2 Steering Wheel 3F-2 Control Buttons 3F-3 Delay Relay and Interface Module 3F-3

CONTROLS SYSTEM COMPONENTS

Figure 1

The steering wheel remote control pad (1) is removed by carefully prying out the pad, and disconnecting the horn (3) and controls (4) leads. The delay relay (9) and interface module (8) convert and relay the control button signals to the proper function.

CONTROL BUTTON FUNCTIONS

Steering wheel control buttons allow remote control of the following functions (see Figure 2):

FAN -Changes heater/AC blower fan speeds. TEMP -Changes temperature setting of heater/AC. MODE -Changes heater/AC mode options: FADE - Changes speaker balance, front to rear. MUTE -Turns sound off AM/FM -Switches between AM and FM bands. PRE-SET -Selects pre-set stations. VOL -Volume control of radio and tape deck. SEEK -Seeks the next station, either up or down the radio band.

DIAGNOSIS

Refer to page 8A-150 of this manual. Refer to Section 9A-Radio System and Antennas for Steering Wheel Controls operation.

UNIT REPAIR CONTROL BUTTON ASSEMBLY ----------------------- Figure 3

Remove or Disconnect

1. Pry out control button assembly with thin bladed screwdriver along top edge of assembly.

2. Disconnect steering wheel control connector.

Install or Connect

1. Connect steering wheel control connector.

2. Push control button assembly into place.

CONTROL BUTTON ASSEMBLY BULBS

These bulbs are not replaceable at the dealership. For bulb replacement, send the control button assembly to a Delco repair shop.

HORN OPERATION

Horn operation is not affected by the steering wheel control system or removal of the control button assembly.

STEERING WHEEL

Figure 4 Tools required: J1859-03 Steering Wheel Puller

Remove or Disconnect

1. Horn pad assembly (see preceding steps).

2. Retainer and nut.

3. Mark steering shaft and steering wheel to ensure proper alignment during reinstallation.

4. Steering wheel with J1859-03.

NOTICE: On cars equipped with steering wheel control option, do not install J1859-03 bolts beyond five full turns. Damage to electronic components under steering wheel may result if this procedure is not followed.

Install or Connect

1. Align mark on steering wheel with mark on shaft.

2. Nut to 41 N.m (30 lbs. ft.).

3. Retainer.

4. Horn pad assembly (see preceding steps).

Figure 5

Remove or Disconnect

1. Control button assembly (see preceding steps).

2. Rocker Button (with arrows)

Pull up at edge with arrow until button comes off pivot post.

3. Push Button

Pull up at edge carefully

When button comes out of actuators they may loosen. Check proper placement of actuators.

Install or Connect

1. Rocker Button(with arrows)

Properly position rocker button on pivot posts and press down until seated.

2. Push Button

Push button evenly on both sides until both sides of button are seated in actuator.

3. Make sure rubber lightshield is in place.

4. Control button assembly (see preceding steps).

COMPONENT LOCATION

Item Description Figure Connector ---- ----------- ------ --------- Amplifier Under RH front seat 201-20-A 202-11

Assembly Line Below LH side I/P, left of steering 201- 6-A 202-13 Diagnostic Link column (ALDL) Connector

Fuse Block Mounted in LH side of I/P. behind 201- 8-A trim panel

Horn Switch Top of steering column, in 201- 8-A steering wheel

HTR A/C and Radio Inside steering column, near base 201- 7-B Control Interface Module Steering Wheel Pad In steering wheel 201- 7-A Switch And Electronics Module Turn Signal Cancell Underside of steering column, 201- 7-A Cam Assembly at slip rings

Turn Signal Switch Top of steering column, 201- 7-C below steering wheel

C200 (60 cavities) Behind center of I/P 201-11-B 202-1

C203 (30 cavities) Behind center of I/P 201-11-B 202-3

C206 (48 cavities) Behind I/P, left of steering column 201- 9-A 202-3

C310 (7 cavities) At LH front door sill 201-16-A 202-7

C311 (10 cavities) Below LH front door sill 201-16-A 202-7

C330 (10 cavities) Below RH front door sill 201-16-A 202-8

C361 (8 cavities) Under rear of center console 201-10-A 202-8

G200 Behind I/P, at LH shroud 201- 8-C

G201 Behind I/P, at RH shroud 201-14-A

S200 Composite harness, at LH shroud 201-12-D S204 Composite harness, at LH shroud 201-12-D

S207 Composite harness, at RH rear 201-12-D door sill

S209 Composite harness, at RH rear 201-12-D door sill

S213 I/P harness, behind LH side of I/P 201- 6-A

S214 I/P harness, behind center of I/P 201- 6-A

S215 Composite harness, near top LH 201- 8-A side of I/P

S217 I/P harness, behind LH side of I/P 201- 6-A

S218 Composite harness, behind top RH 201-14-A side of I/P

S219 Composite harness, under RH 201-20-A front seat

S222 Composite harness, under RH 201-20-A front seat

S223 Composite harness, under 201-20-A passenger's seat

S224 Composite harness, at RH shroud 201-14-A

S228 Composite harness, at RH shroud 201-14-A

S237 Composite harness, at RH shroud 201-14-A

S238 Composite harness, at upper 201- 8-C LH shroud

S243 Composite harness, behind 201-11B center of I/P

S245 Composite harness, at upper LH shroud 201- 8-C

S249 Composite harness, at RH shroud 201-14-A

S255 I/P harness, behind center of I/P 201- 6-A

S287 Composite harness, behind LH side 201- 9-A of I/P S293 I/P harness, behind center of I/P 201- 6-A

S294 I/P harness, behind RH side of I/P 201- 6-A

S297 I/P harness, behind center of I/P 201- 6-A

S298 I/P harness, behind RH side of I/P 201- 6-A

S310 Console harness, under rear of 201-10-A center console S311 Console harness, under rear of 201-10-A center console S314 Composite harness, under 201-20-A passenger's seat

TROUBLESHOOTING HINTS

1. Check Fuse 11.

2. Check Fuse 4.

3. Check Fuse 14 by operating the Park Lights.

4. Check that the Antenna connector and the Antenna Coaxial Cable are properly connected.

5. Adjusting the Radio controls will change the operation of the sound system. Consult the Delco Sound Service Guide for information regarding the operation of these controls.

6. Before troubleshooting a suspect Speaker, check all connections to that Speaker.

7. For proper noise diagnosis, take the car outside where signals are strong. Close the hood, and keep away from metal buildings or sources of radio interference.

8. Ignition noise on FM may indicate a defective Ignition System.

9. Coated screws or bolts can cause a poor ground condition. Scrape ground screw clean of any paint or varnish.

Go to System diagnosis for diagnostic teste.

For removal and replacement procedures see Section 8C.

If CAMS diagnostic equipment is available, it may be used to diagnose Radio system components of the Serial Data Line.

SYSTEM DIAGNOSIS

Refer to the vehicle owner's manual for radio system operation.

Select a symptom from the Symptom Table and follow the diagnosis given.

SYMPTOM TABLE

SYMPTOM FOR DIAGNOSIS ------- ------------- Radio/Clock/ Radio display forms incomplete numbers Send the Radio to Cassette or letters an authorized Player/ Compact Radio plays, but one or niore of the AC-Delco repair Disc Player/ Radio controls do not operate station Equalizer Radio functions operate correctly but the Cassette Player, or Compact Disc Player, or Equalizer does not work properly

Not all or no functions operate from the Radio, but all operate from the Steering Wheel Pad Switch And Electronics Module

Radio, Heater and A/C Controls and Steering Do Test K Wheel Controls (if equipped) do not operate ----------------------------------------------------------------------------- Radio/Clock/ Some functions do not work from both the Send the Radio to Cassette Steering Wheel Pad Switch And Electronics an authorized Player/ Module and the Radio, but other functions do AC-Delco repair Compact/ station Disc Player Radio display scans past all radio Do Test B Equalizer frequencies when in Seek or Scan modes. Hiss is present over most radio stations

Radio noise is excessive Do Test C

Time or radio display does not appear when Do Test D the Ignition Switch is turned to RUN or ACCY

Power Antenna does not extend with the See Power Antenna Radio ON (Section 8A-151) ------------------------------------------------------------------------------ Speakers One or more speakers do not operate, both Do Test E subwoofers cannot be heard when amplifier is on

Both subwoofers lack bass response, other Do Test F speakers operate correctly

Both subwoofers are operational, but their Do Test G volume cannot be controlled by adjusting the gain control switch ------------------------------------------------------------------------------ Radio Radio display does not dim or goes blank Do Test A Illumination with the Headlights or Park Lights ON

Radio face or buttons do not light up with the Headlights or Park Lights ON ------------------------------------------------------------------------------ Steering Only some functions operate from the Send the Steering Wheel Steering Wheel Pad Switch And Electronics Wheel Pad Switch Controls Module, but all operate from the Radio And Electronics and Heater and A/C Controls Module to an authorized AC-Delco repair station Steering Wheel Pad Switch And Electronics Do Test H Module illumination does not come on with the Headlights or Park lights ON

Steering Wheel Controls do not operate at Do Test I some steering wheel positions, or Steering Wheel Pad Switch And Electronics Module panel lights flicker as steering wheel is turned

None of the Steering Wheel Controls operate Do Test J

A: RADIO DISPLAY DOES NOT DIM OR GOES BLANK WITH THE HEADLIGHTS OR PARK LIGHTS ON; RADIO FACE OR BUTTONS DO NOT LIGHT UP WITH THE HEADLIGHTS OR PARK LIGHTS ON (May be caused by open dimming circuits)

1. Disconnect Radio connector C1. Turn Park Lights ON and adjust Panel Lights to full brightness.

2. Measure voltage between pin 6 (BRN) of connector C1 and ground.

If battery voltage is present, go to step 3; otherwise, repair BRN (9) wire.

3. Measure voltage between pin 7 (GRY) of connector Cl and ground.

If battery voltage is present. go to Step 4; otherwise. repair GRY (8) wire.

4. Send the Radio to an authorized AC-Delco repair station.

B: RADIO DISPLAY SCANS PAST ALL RADIO FREQUENCIES WHEN IN SEEK OR SCAN MODES; HISS IS PRESENT OVER MOST RADIO STATIONS

(May be caused by a faulty antenna connection, antenna coaxial cable, Antenna or Radio)

- Ignition Switch in RUN or ACCY - Check the Antenna Coaxial Cable at the Radio and Antenna. They should be clean and tight - Connect a known good Antenna and Antenna Coaxial Cable at the Radio connector

Does the Radio now operate? | |---------------------------------------------------| | | YES NO | | | | - Reconnect the original Antenna Coaxial - Send the Radio to an Cable at the Radio authorized AC-Delco - Connect a known good Antenna, using the original repair station Antenna Coaxial Cable

Does the Radio now operate? | |---------------------------------------------------| | | YES NO | | | | Replace the Antenna Replace the Antenna Coaxial Cable

C: NOISE DIAGNOSIS

Unplug the Antenna at the back of the Radio.

If the noise persists, it is coming in the Radio wiring. Refer to the chart for a possible cause and repair action.

If noise disappears, see symptom 8 in chart.

NOISE DIAGNOSIS TEST

SYMPTOM POSSIBLE CAUSE REPAIR ACTION ------- -------------- ------------- 1. Harsh popping noise Ignition noise Perform the steps under that changes with Ignition Noise, page 150-14 engine rpm

2. High whine (like a Generator noise Add filter package 1224205 siren) that changes to power and/or memory lead with engine rpm to the Radio By-pass the Generator output with a 250 MFD 100 v capacitor (See Fig.3, page150-14) Install a braided ground strap on the Radio (See Fig. 1. page 150-14) Run a direct wire from the Battery (+) to the Generator Repair or replace Generator

3. Noise occurs only Condition in that Install filter package when an accessory accessory 1224205 in the power is on lead(s) to that accessory (See Fig. 2, page 150-14) Install a .5 MFD by-pass capacitor at the power lead to that accessory Consult Delco Sound Service Guide

4. All stations weak, Defective Antenna or Do Test B noisy (both AM lead-in wire and FM)

5. (AM only)weak, noisy Defective antenna or Do Test B lead in wire or AM alignment

6. (FM only)weak, noisy FM alignment Send the Radio to an authorized AC-Delco repair station 7. Noise present with ECM or Digital See the Delco Sound engine not running Cluster Service Guide

8. Noise stops when Antenna noise Replace the defective Antenna Antenna is unplugged with a good Antenna. If from back of Radio noise disappears, repair or replace the defective Antenna. Check Antenna ground, Coaxial Cable braid, and grounds at connectors. If noise persists with replacement Antenna, the problem must be repaired at the source of noise (Generator, Ignition System accessory, etc.). See the Delco Sound Service Guide for noise "sniffing" procedures.

For more detailed noise repair procedures consult the Delco Sound Service Guide. Service procedures are given for:

- Accessory noises - CB Antennas and noise - Computer noise - Shielding of wiring and components - Locating vehicle noise

IGNITION NOISE

Try the following in the given order:

1. Check for loose or defective spark plug wire.

2. Check for defective spark plug.

3. Move all wiring away from HEI and spark plug wires.

4. Reroute spark plug wires lying against anything that could possibly transmit noise to the Radio (car wiring or sensor leads that travel into the passenger compartment).

5. Check the engine to ground connection. Install a braided ground strap if necessary.

D: TIME OR RADIO DISPLAY DOES NOT APPEAR WHEN THE IGNITION SWITCH IS TURNED TO RUN OR ACCY

(May be caused by an open ignition wire, battery wire, or an inoperative Radio)

- Ignition Switcn in RUN or ACCY - Measure voltage at Radio connector C1 terminal 9 (YEL)

Is battery voltage present? | |--------------------------------------| | | YES NO | | | | - Measure voltage at Radio connector - Check Fuse 4 and YEL (43) C1 terminal 10 (ORN) wire for an open

Is battery voltage present? | |--------------------------------------| | | YES NO | | | | Is there a good ground at Radio - Check Fuse 11 and ORN (40) connector C1 terminal 5 (BLK)? wire for an open | |-------------------------------------| | | YES NO | | | | - Send the Radio to an authorized - Check BLK (150) wire for an open AC-Delco repair station

E: ONE OR MORE SPEAKERS DO NOT OPERATE; BOTH SUB WOOFERS CANNOT BE HEARD WHEN AMPLIFIER IS ON

(May be caused by a faulty speaker, Radio, Amplifier (if equipped), Gain Control Switch (if equipped) or bad wire(s))

Note: Do not leave 1.5 volt battery connected for more than one second. Prolonged connection could damage speaker

- Disconnect suspect speaker connector and connect a known good 1.6 volt battery across the speaker terminals (if suspect speaker is a rear speaker, see schematic for terminal identifi- cation)

Does the speaker pop? | |---------------------------------| | | YES NO | | | | Is suspect speaker a subwoofer? - Replace the speaker | |---------------------------------| | | YES NO | | | | Are both sub woofers inoperative? - Turn Radio ON (high volume) and tune | to a strong signal | - Set balance and/or fade toward the | suspect speaker | - Measure AC voltage at the Radio | output to the suspect speaker |--------------| Does the meter reading vary above | | 3 volts? | | | YES NO |------------------------| | | | | | - Repair the open in the YES NO EA wires between the | | Amplifier and the Repair the open in the EB suspect speaker wire(s) between the Radio and the suspect speaker

EB | Disconnect suspect speaker Measure the resistance to ground at termi- nals A and B of the suspect speaker.

Is the resistance less than 20 ohms? | |----------------------------------------------| | | YES NO | | | | Does the sound system have an Send Radio to an authorized Amplifier? AC-Delco repair station | |---------------------------------------------| | | YES NO | | | | Disconnect the Amplifier connector Repair the shorted wires Repeat the above measurement at the speaker terminal where the resistance to ground was less than 20 ohms.

Is the resistance less than 20 ohms? | |----------------------------------------------| | | YES NO | | | | Repair the shorted wires Send the Amplifier to an authorized AC-Delco repair station

EA | Disconnect the Amplitier connector

Radio ON Measure voltage at connector terminal 13 (PNK) Is battery voltage present? | |--------------------------------------------| | | YES NO | | | | Measure voltage between connector Check the PNK (143) wire for an open terminals 13 (PNK) and 14 (BLK) or short to ground. Is battery voltage present? Is the PNK (143) wire OK? | | |------------------| |---------------------| | | | | YES NO YES NO | | | | | | | | Reconnect the Repair/replace Send the Radio to Repair/replace Amplifier connector the BLK (150) an authorized as necessary Gain Control Switch wire as AC Delco Repair connected necessary Station Radio ON

Measure voltage at Gain Control Switch connector terminal A (LT GRN/BLK) Are approximately 8 volts present? | |-------------------------| | | YES NO | | | | EC Check the LT GRN/BLK (1002) wire for an open or short to ground. Is the LT GRN/BLK (1002) wire OK? | |---------------------------------| | | YES NO | | Send the Amplifier to an authorized Repair/replace as AC Delco repair station necessary

EC | | Measure voltage between Gain Control Switch terminal F (PNK) and ground.

Is battery voltage present? | |---------------------------------------------------| | | YES NO | | Measure voltage between terminal F (PNK) and Repair/replace PNK (143) terminal D (BLK) of the Gain Control Switch. wire

Is battery voltage present? | |---------------------------------------------------| | | YES NO | | | | Turn Gain Control Switch ON Repair/replace the BLK Measure voltage between terminal 3 (GRY/WHT) (150) wire of the Amplifier connector and ground. Is battery voltage present? | |------------------------| | | YES NO | | | Is the GRY/WHT (1245) wire between the Am- ED plifier and the Gain Control Switch OK? | |-----------------------------| | | YES NO | | | | Replace the Gain Control Switch Replace the GRY/WHT (1245) wire

ED | Disconnect the Amplifier connector Measure resistance between terminal 9 (DK GRN/ WHT) of the Amplifier connector and ground

Is there continuity to ground? | |-------------------------------------| | | NO YES | | Reconnect the Amplifier connector Disconnect the Gain Control Switch Radio ON (high volume) tuned to a strong station Repeat the above measurement Measure AC voltage between terminals 12 (DK BLU/WHT) Is there continuity to ground? and 15 (BLK/LT GRN) of | Amplifier connector. |------------------| | | NO YES | | | | Does the meter reading vary above Replace the Gain Repair/replace 3 volts? Control Switch the DK GRN/WHT | (1001) wire |--------------------| | | YES NO | | | | Repair the open in the Check the DK BLU/WHT DK BLU/WHT (1243) (1243) and BLK)LT GRN and/or BLK/LT GRN (1242) wires for an (1242) wires open or short to ground Are the DK BLU/WHT (1243) and the BLK/LT GRN(1242) wires OK? | |---------------| | | NO YES | | Repair/replace the Send the Amplifier wires as necessary to an authorized AC Delco Repair station

F: BOTH SUB WOOFERS LACK BASS RESPONSE, OTHER SPEAKERS OPERATE CORRECTLY

(May be caused by a faulty Amplifier or a bad wire)

Disconnect Amplifier connector

Turn Radio ON (high volume) and tune to a strong signal

Set balance and/or fade so that all speakers are operational (except sub wooters)

Measure the AC voltage between terminals 1 (LT GRN) and 2 (DK GRN) of the Amplifier connector

Does the meter reading vary above 3 volts? | |-------------------------------------------| | | YES NO | | | | Measure the AC voltage between Repair/replace LT GRN (200) terminals 4 (TAN) and 5 (GRY) and/or DK GRN (117) wires of the Amplifier connector Does the meter reading vary above 3 volts? | |--------------------------------------------| | | YES NO | | | | Measure the AC voltage between Repair/replace TAN (201) terminals 10 (BRN) and 11 (YEL) and/or GRY (118) wires of the Amplifier connector

Does the meter reading vary above 3 volts? | |---------------------------------------------| | | YES NO | | | | Measure the AC voltage between Repair/replace BRN (199) terminals 7 (DK BLU) and 8 (LT BLU) and/or YEL (116) wires of the Amplifier connector

Does the meter reading vary above 3 volts? | |----------------------------------------------| | | YES NO | | | | Send Amplifier to an authorized Repair/replace DK BLU (46) AC-Delco repair station and/or LT BLU (115) wires

G: BOTH SUB WOOFERS ARE OPERATIONAL BUT THEIR VOLUME CANNOT BE CONTROLLED BY ADJUSTING THE GAIN CONTROL SWITCH

(May be caused by a faulty Amplifier, Gain Control Switch, or a bad wire)

Turn Radio ON (high volume) and tune to a strong signal

Turn Gain Control Switch ON and adjust it between MIN and MAX

Measure voltage between terminal B (DK GRN/WHT) of the Gain Control Switch connector (connected) and ground

Does the voltage vary between 4 and 8 volts as the Gain Control Switch is adjusted from MIN to MAX? | |----------------------------------------------| | | YES NO | | Measure voltage between terminal Measure voltage between terminals 9 (DK GRN/WHT) of the Amplifier A (LT GRN/BLK) and D (BLK) of connector (connected) and ground the Gain Control Switch

Does the voltage vary between 4 Is 8 volts measured? and 8 volts as the Gain Control | Switch is adjusted from MIN to MAX? | | |------------------| |---------------| | | | | | | YES NO YES NO | | | | | | | | Send the Amplifier Repair the open in the Replace the Gain Repair the to an authorized DK GRN/WHT (1001) wire Control Switch open in the AC-Delco repair BLK (150) station wire

H: STEERING WHEEL PAD SWITCH AND ELECTRONICS MODULE ILLUMINATION DOES NOT COME ON WITH THE HEADLIGHTS OR PARK LIGHTS ON

(May be caused by faulty Steering Wheel Pad Switch And Electronics Module, burnt out bulbs, open dimming circuit, or misalignment of components)

Headlights or Park Lights ON

Panel Lights set to maximum brightness

Measure voltage at connector C206 terminal A2

Are 8 volts or more measured? | |----------------------------------------------| | | YES NO | | | | Remove the Steering Wheel Pad Switch Repair the open And Electronics Module (Refer to Section GRY (8) wire 3B4 for removal procedures)

Connect the Horn Tower Test Adapter J37608 between the Steering Wheel Pad Switch And Electronics Module and the Turn Signal Cancel Cam Assembly

Headlights or Park Lights ON

Panel Lights set to maximum brightness

Measure voltage between the GROUND and ILLUM probe cavities at the Switch Cluster section of the J37608 Test Adapter

Is battery voltage present? | |----------------------------------------| | | YES NO | | | | Check/replace the Steering Check wiring between C206 and Wheel Pad Switch and Turn Signal Cancel Cam Assembly. Electronics Module Remove the Turn signal cancel Cam Illumination bulbs Assembly. Inspect the Slip Rings on the Turn Signal Cancel Cam Assembly and the spring loaded contacts on the Turn Signal Switch. Replace as necessary. Incorrect or missing lubricant on the Cam can cause premature failure. Take care to keep lubricant or any foreign material away from the LEDs and receptors as it will hinder or prevent proper operation. See Parts And Illustrations Catalogue for required special lubricant.

I: STEERING WHEEL CONTROLS DO NOT OPERATE AT SOME STEERING WHEEL POSITIONS, OR STEERING WHEEL PAD SWITCH AND ELECTRONICS MODULE PANEL LIGHTS FLICKER AS WHEEL IS TURNED

(May be caused by faulty Turn Signal Cancel CamAssembly, Turn Signal Switch, or dirty or misaligned components)

Remove the Steering Wheel Pad Switch And Electronics Module (Refer to Section 3B4 for removal procedures)

Connect the Horn Tower Test Adapter J37608 between the Steering Wheel Pad Switch And Electronics Module and the Turn Signal Cancel Cam Assembly

Engine running

Headlights or Park Lights ON

Panel Lights at maximum brightness

Measure voltage at the J37608 Switch Cluster probe cavities while slowly turning the Steering Wheel (Voltage must not vary as wheel is turned)

ILLUM and GROUND BATTERY VOLTAGE DATA OUT and GROUND BATTERY VOLTAGE

Are the measurements listed above OK? | |-------------------------------------| | | YES NO | | | | Remove the Turn Signal Cancel Remove the Turn Signal Cam Assembly Cancel Cam Assembly. Inspect the slip rings on the Turn Ignition Switch in ACCY or RUN Signal Cancel Cam Assembly and the spring loaded contacts on the Cover one of the Turn Signal Switch Turn Signal Switch. Replace as Receiver/Transmitters with black necessary. Incorrect or missing electrical tape (see Fig. 2) lubricant on the Cam can cause premature failure. Take care to Aim an incandescent light at the Turn keep lubricant or any foreign Signal Switch Light Receiver/ material away from the receiver/ Transmitter (a flashlight will do) transmitter as it will hinder or prevent proper operation. See Measure voltage at ALDL connector Parts And illustrations Catalogue terminal "J" for required special lubricant.

Is the measurement approximately 1 volt or less? | |------------------------------------------| | | YES NO | | | | Repeat the above instructions with the Replace the Turn Signal Switch opposite Turn Signal Switch Receiver/ Transmitter covered

Is the measurement approximately 1 volt or less? | |-------------------------------------------| | | YES NO | | Replace the Turn Signal Cancel Cam Replace the Turn Signal Switch Assembly

J: STEERING WHEEL CONTROLS DO NOT OPERATE BUT RADIO AND HEATER AND A/C CONTROLS ARE OK

(May be caused by faulty HTR-A/C And Radio Control Interface Module, Turn Signal Switch, Turn Signal Cancel Cam Assembly, Steering Wheel Pad Switch And Electronics Module, or an open circuit.)

Connect bi-directional scan tool at ALDL Connector

Ignition Switch in ACCY or RUN

Perform component identification using scan tool

Does scan tool show Radio is present? | |-------------------------------------------| | | NO YES | | | | Check DK GRN (835) wire for an open Does scan tool show that steering between Radio and ALDL Connector Wheel Controls are present? | Is this wire OK? | | |------------------------| |-----------------| | | | | | | NO YES YES NO | | | | | | | | Repair wire as Send Radio to an Replace the Follow instruc- necessary authorized Steering Wheel Pad tions given on AC-Delco repair Switch And page 150-27, station Electronics Module following Fig 1

J: STEERING WHEEL CONTROLS DO NOT OPERATE BUT RADIO AND HEATER AND A/C CONTROLS ARE OK

J37608 Steering Wheel Control Adapter connected (see FIG 1)

Ignition Switch in RUN

Measure voltage at terminal probe cavities in numerical order (1,2,3, etc.)

J37608 probe terminals agree with schematic labels. For example, "DATA IN" on the Switch Cluster side of J37608 is the same as "DATA IN" on the Turn Signal Cancel Cam Assembly on the schematic.

Test Explanation: Steps 1,2,5, and 6 verify that corresponding power or ground circuits are OK

Steps 3 and 4 verify power of ground circuits in the HTR-A/C and Radio Control Interface Module

Step 7 verifies turn signal cancel cam assembly internal continuity by checking for voltage

Step 8 verifies Steering Wheel Pad Switch and Electronics Module "DATA IN" continuity

Step 9 verifies HTR-A/C and Radio Control Interface Module Voltage regulation circuit

Step 10 verifies Turn Signal Switch transmitter internal continuity by checking for voltage

Step 11 verifies HTR-A/C and Radio Control Interface Module "DATA IN" circuit continuity

J: STEERING WHEEL CONTROLS DO NOT OPERATE BUT RADIO AND HEATER AND A/C CONTROLS ARE OK

Jumper J37608 Switch Cluster terminals "DATA OUT" and "GROUND" as shown

Measure in numerical order

Test Explanation: The jumper simulates a ground signal from the Steering Wheel Pad Switch And Electronics Module. If the Turn Signal Cancel Cam Assembly transmitters and Turn Signal Switch receivers are operating, a ground signal will be transmitted through the optical slip ring and will be measured at the J37608 E & C Interface probe cavity "DATA OUT" If the HTR-A/C And Radio Control Interface Module is OK, the ground signal will be sent through the HTR-A/C And Radio Control Interface Module and will appear at the J37608 E & C Interface "DATA BUS" cavity.

J: STEERING WHEEL CONTROLS DO NOT OPERATE BUT RADIO AND HEATER AND A/C CONTROLS ARE OK

Disconnect jumper from the previous step

Jumper ALDL terminal J (DK GRN) to ground

Measure in numerical order

If all checks are OK, replace the Steering Wheel Pad Switch And Electronics Module

Test Explanation: The jumper at ALDL terminal J simulates a data signal from the Radio. If the DK GRN (835) wire is OK, a ground signal will appear at the J37608 "DATA BUS' terminal. If the HTR-A/C And Radio Control Interface Module is OK, a ground signal will appear at the J37608 E & C Interface "DATA IN" cavity. If the Turn Signal Switch transmitters are operating, the ground signal will appear at the E & C Interface "DATA OUT" cavity. If the Turn Signal Cancel Cam Assembly receivers are OK, the ground signal will appear at the Switch Cluster "DATA IN" cavity. If all signals are good, Steering Wheel Pad Switch And Electronics Module must be at fault.

J: STEERING WHEEL CONTROLS DO NOT OPERATE BUT RADIO AND HEATER AND A/C CONTROLS ARE OK ISOLATION TEST

Perform only the step referenced

Test Explanations: Step A is checking for a short to ground in the Turn Signal Cancel Cam Assembly. If battery voltage appears, the Turn Signal Cancel Cam is shorted to ground. If zero volts are measured, the Steering Wheel Controls are either shorted to ground or open. Step B is checking for a short to ground in the Turn Signal Switch. If resistance measurement is not infinite, the Turn Signal Switch is shorted and the HTR-A/C And Radio Control Interface Module is also defective. If resistance is infinite, the HTR-A/C And Radio Control Interface Module 5 volt regulated supply is not operating.

J: STEERING WHEEL CONTROLS DO NOT OPERATE BUT RADIO AND HEATER AND A/C CONTROLS ARE OK

TURN SIGNAL SWITCH OPTICAL TEST

Remove the Turn Signal Cancel Cam Assembly

Ignition Switch in ACCY or RUN

Cover one of the Turn Signal Switch Receiver/Transmitters with black electrical tape

Aim an incandescent light at the Turn Signal Switch Light Receiver/Transmitter (a flashlight will do)

Measure voltage at ALDL Connector terminal J (DK GRN)

Is the measurement approximately 1 volt or less? | |------------------------------------------| | | YES NO | | | | Repeat the above instructions with the Replace the Turn opposite Turn Signal Switch Receiver/ Signal Switch Transmitter covered

Is the measurement approximately 1 volt or less? | |------------------------------------------| | | YES NO | | | | Replace the Turn Signal Cancel Cam Replace the Turn Assembly. See Parts And Illustrations Signal Switch Catalogue for required special lubricant.

K: RADIO, HEATER AND A/C AND STEERING WHEEL CONTROLS DO NOT OPERATE

(May be caused by a short to power or ground in a component or 835 data line)

Ignition Switch in ACCY or RUN

Measure voltage to ground at ALDL terminal J (DK GRN)

Are 9-12 volts measured? | |--------------------------------------------------| | | NO YES | | | | If vehicle is not equipped with If vehicle is not equipped with Steering Wheel Controls, skip Steering Wheel Controls, skip to the "NO" path to the "NO" path

Disconnect HTR-A/C And Radio Disconnect HTR-A/C And Radio Control Interface Module connector Control Interface Module connector

Attempt to operate the Radio from Do the Radio controls operate? Radio controls | | Does Radio respond? | | |---------------------| |----------------------| | | | | | | NO YES YES NO | | | Disconnect Heater Reconnect the Replace the Disconnect Heater and A/C Control HTR A/C And HTR A/C And And A/C Assembly connector Radio Control Radio Control Control Assembly Interface Module Interface connector connector Module Do the Radio Attempt to operate Disconnect the controls now the Radio from Radio Steering Wheel operate? controls Pad Switch and | Electronics Module | connector | | Does Radio respond? Does the Radio | | operate from Radio | | controls? |-----------| |-------| | | | | | |-----------| | | | | | | | | NO YES NO YES NO YES | | | | | | KA Send the KC Send the Steering KB Send the Heater and Heater and Wheel Pas Switch A/C Control A/C Control And Electronics Assembly to an Assembly to Module to an authorized AC-Delco an authorized authorized AC-Delco repair station AC-Delco repair station repair station

KA KB | | | | Disconnect Radio connector C3 Disconnect Radio connector C3

Measure resistance between Radio connector Measure voltage at ALDL C3 terminal 7 (DK GRN) and ground terminal J (DK GRN)

Is infinite resistance measured? Is 0 volts measured? | | | | |--------------------------| |-------------------| NO YES NO YES | | | | Repair DK GRN Send Radio to Check DK GRN (835) Send Radio to (835) wire for an authorized wire for a short an authorized a short to ground AC-Delco repair to battery AC-Delco station repair station

KC | | Remove the Turn Signal Cancel Cam Assembly

Cover the Turn Signal Switch Transmitter/Receivers

Does the Radio now operate? | |----------------------------------------------------| | | NO YES | | | Replace the Turn Signal Cancel | Cam Assembly. See Parts And | Illustrations Catalogue for | required special lubricants. | | Connect the J37608 steering wheel test adapter between the Steering Wheel Pad Switch And Electronics Module and Turn Signal Cancel Cam Assembly and between the HTR-A/C And Radio Control Interface Module connector with the HTR-A/C And Radio Control Interface Module disconnected

Ignition Switch in ACCY or RUN

Measure voltage between J37608 Switch Cluster probe cavity "ACC B+" and E & C interface probe cavity "DATA OUT"

Is battery voltage present? | |-----------------------------------------| | | NO YES | | KD Replace the Turn Signal Switch. See Parts And Illustrations Catalogue for required special lubricant.

KD | | J37608 connected as above

Measure voltage between J37608 Switch Cluster probe cavity "ACC B+" and E&C Interface cavity "DATA IN"

Is Battery voltage present? | |------------------------------------------------| | | NO YES | | Replace the HTR-A/C And Radio Replace the Turn Signal Switch. Control Interface Module See Parts and Illustrations Catalogue for required special lubricant.

CIRCUIT OPERATION

RADIO

The Radio receives voltage through four paths: 1) Fuse 4 to the On-Off Switch from the YEL wire; 2) Fuse 11 and the ORN wire which keeps the solid state clock, date, and Radio station memory circuits alive when the Ignition Switch is turned OFF; 3) an Instrument Panel lamp voltage controlled by Panel/Interior Light Control for the Radio Panel Light (GRY wire); and 4) a Digital Dim Signal to dim the Radio Station numbers at night. This signal comes from the Head/Park Light Switch.

The Radio On-Off Switch also switches battery voltage to the PNK wire to operate the Power Antenna. The PPL/YEL (724) circuit sends dimming information to the Heater And A/C Control Assembly.

The Steering Wheel Controls System consists of several components. They include the following:

Steering Wheel Control Head Turn Signal Cancel Cam Assembly Turn Signal Switch HTR-A/C And Radio Control Interface Module Radio

STEERING WHEEL CONTROL HEAD

The Steering Wheel Control Head controls the radio by creating voltage pulses that correspond to different radio control functions. These signals are sent to the optical receiver/transmitters in the Turn Signal Cancel Cam As- sembly. The Steering Wheel Control Head also receives data line signals via the Turn Signal Cancel Cam Assembly. The signals received by the Steering Wheel Control Head are used to determine when the data line is free of other signals so it may transmit.

The Steering Wheel Control Head receives power, illumination and ground via slip rings between the Turn Signal Switch and the Turn Signal Cancel Cam.

TURN SIGNAL CANCEL CAM ASSEMBLY

The Turn Signal Cancel Cam Assembly includes five solid state infrared transmitter/receiver units. These units, along with two identical optical units in the Turn Signal Switch, are used to send optical signals between the steering wheel and steering column. The optical units are arranged so they are always in sight of each other, thus forming an optical slip ring. The Turn Signal Cancel Cam incorporates circuitry which changes the signals from optical to electrical and vice-versa. The Turn Signal Cancel Cam Assembly receives power, ground and illumination power through 3 of its 4 slip rings from the Turn Signal Switch brush contacts. The horn signal is sent through the fourth slip ring.

TURN SIGNAL SWITCH

The Turn Signal Switch receives optical signals from the Turn Signal Cancel Cam Assembly and converts them to electrical signals that are sent to the HTR-A/C And Radio Control Interface Module. It also receives electrical signals from the HTR-A/C And Radio Control Interface Module and converts them to the Turn Signal Cancel Cam Assembly. The Turn Signal Switch sends power, ground and illumination power to the Turn Signal Cancel Cam Assembly through its brush contacts.

HTR-A/C AND RADIO CONTROL INTERFACE MODULE ------------------------------------------ The HTR-A/C And Radio Control Interface Module receives electrical voltage pulses from the Turn Signal Switch and sends these signals to the Radio over the serial data line. It also receives signals from other devices over the serial data line and sends these signals to the Turn Signal Switch. The HTR-A/C And Radio Control Interface Module is used to shape the signal pulses, to separate the send and receive pulses, and to convert from a one to a two wire data line.

RADIO

The Radio receives instructions over the serial data line from the HTR-A/C And Radio Control Interface Module in the form of voltage pulses. The Radio then responds to these voltage pulses by adjusting its operation accordingly,

AMPLIFIER

The Amplifier is turned on when the Radio is ON and the Gain Control Switch is ON. supplying battery voltage to the Amplifier Mute Input.

The Amplifier's inputs are connected in parallel with the speakers. Its outputs drive one of the two coils in each of the Woofers. The same signal drives both speakers. Amplifier power level may be controlled by adjusting the Gain Control Switch.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.