SERVICE MANUAL UPDATE SEC. 8A ELECT.-MANUAL A/C (REV. DIAG.)
Subject: SERVICE MANUAL UPDATE SECTION 8A ELECTRICAL DIAGNOSIS MANUAL AIR CONDITIONING (C61) AIR DELIVERY (REVISED DIAGNOSTIC PROCEDURE)
Models Affected: 1992 BONNEVILLE MODELS
Diagnosis for "Air Temperature Control Does Not Operate Correctly" symptom found in the service manual contains an error that could lead to confusion and misdiagnosis.
The following revised pages should be used for proper system diagnosis:
1992 Bonneville SE, Page 8a-65-4 1992 Bonneville SSE/SSEI, Page 8a-65-4
Please update your respective service manual accordingly.
PONTIAC BONNEVILLE SE
AIR CONDITIONING: AIR DELIVERY MANUAL AIR CONDITIONING (C61)
B: HVAC ASSEMBLY INPUT TEST --------------------------- Measure: VOLTAGE
At: HEATER AND A/C CONTROL ASSEMBLY CONNECTOR C2 (Connected)
Conditions:
---------- o Ignition Switch: RUN o Temperature: HOT
Measure Correct For between Voltage Diagnosis ------- ------- --------- H (BRN) & Battery See 1 Ground
H (BRN) & F Battery See 2 (BLK)
H (BRN) & E Battery See 4 (DK BLU)
F (BLK) & G Battery See 3 (WHT/BLK)
o Temperature: COLD
F (BLK) & G Less than 1 See 4 (WHT/BLK) volt
o If all voltages are correct, go to Test C.
1. Check BRN (50) wire for an open. Check I/P Fuse Block Fuse 17.
2. Check BLK (152) wire for an open.
3. Check WHT/BLK (1236) wire for a short to ground. If OK, replace Heater And A/C Control Assembly.
4. Replace Heater And A/C Control Assembly.
C: ACTUATOR INPUT TEST ---------------------- Measure: VOLTAGE
At: A/C TEMPERATURE VALVE ACUTATOR CONNECTOR (Disconnected)
Conditions:
---------- o Ignition Switch: RUN
o Temperature: HOT
Measure Correct For Between Voltage Diagnosis ------- ------- --------- 10 (BRN) & Battery See Ground
10 (BRN) & Battery See 2 7 (DK BLU)
8 (WHT/ BLK) & Battery See 3 Ground
o If all voltages are correct, check Temperature Valve for sticking or binding. If OK, replace A/C Temperature Valve Actuator.
1. Check BRN (50) wire for an open.
2. Check DK BLU (1199) wire for an open.
3. Check WHT/BLK (1236) wire for an open.
CIRCUIT OPERATION
A/C Evaporator Core ------------------- All air passing through the A/C plenum moves across the A/C Evaporator Core. When the Compressor is on, the core cools and removes moisture from the air.
Inlet and Outlet Valves
The O/S Air-Recirc. Valve, A/C-Defrost Valve and Mode Valve are moved according to the position of the A/C Mode Selector. The Selector contains vacuum valves or switches. These valves apply and remove vacuum to Vacuum Actuators that move the inlet and outlet valves.
The O/S Air-Recirc. Valve is in position A for every A/C Mode Selector position except MAX. The actuator bellows are expanded which opens the O/S Air-Recirc. Valve and lets outside air into the module.
When the A/C Mode Selector is moved to MAX, vacuum is applied to the O/S Air Recirc. Valve Vacuum Actuator. The bellows are drawn in and the Valve is moved to position B. Air from inside the vehicle is pulled into the module.
The Heater-A/C Bi-Level Valve Vacuum Actuator, which controls the Mode Valve, can assume three positions. The Actuator is operated by two bellows and two vacuum switches. With the A/C Mode Selector in MAX, A/C, VENT or DEFROST, vacuum is applied through the WHT hose. The bellows closest to the WHT hose contract, moving the Valve to position A. Air flow is directed toward the windshield outlets or A/C-instrument panel outlets and no air flows from the floor outlets.
PONTIAC BONNEVILLE SSE/SSEi --------------------------- AIR CONDITIONING: AIR DELIVERY MANUAL AIR CONDITIONING (C61)
B: HVAC ASSEMBLY INPUT TEST
Measure: VOLTAGE
At: HEATER AND A/C CONTROL ASSEMBLY CONNECTOR C2 (Connected)
Conditions:
---------- o Ignition Switch: RUN o Temperature: HOT
Measure Correct For Between Voltage Diagnosis ------- ------- --------- H (BRN) & Battery See 1 Ground
H (BRN) & F Battery See 2 (BLK)
H (BRN) & E Battery See 4 (DK BLU)
F (BLK) & Battery See 3 (WHT/BLK)
o Temperature: COLD
F (BLK) & G Less than 1 See 4 (WHT/BLK) volt
o If all voltages are correct, go to Test C.
1. Check BRN (50) wire for an open. Check I/P Fuse Block Fuse 17.
2. Check BLK (152) wire for an open.
3. Check WHT/BLK (1236) wire for a short to ground. If OK, replace Heater And A/C Control Assembly.
4. Replace Heater And A/C Control Assembly.
C: ACTUATOR INPUT TEST ---------------------- Measure: VOLTAGE
At: A/C TEMPERATURE VALVE ACUTATOR CONNECTOR (Disconnected)
Conditions:
---------- o Ignition Switch: RUN o Temperature: HOT
Measure Correct For Between Voltage Diagnosis ------- ------- --------- 10 (BRN) & Battery See 1 Ground
10 (BRN) & Battery See 2 7 (DK BLU)
8 (WHT/ BLK) & Battery See 3 Ground
o If all voltages are correct, check Temperature Valve for sticking or binding. If OK, replace A/C Temperature Valve Actuator.
1. Check BRN (50) wire for an open.
2. Check DK BLU (1199) wire for an open.
3. Check WHT/BLK (1236) wire for an open.
CIRCUIT OPERATION
A/C Evaporator Core ------------------- All air passing through the A/C plenum moves across the A/C Evaporator Core. When the Compressor is on, the core cools and removes moisture from the air.
Inlet and Outlet Valves
The O/S Air-Recirc. Valve, A/C-Defrost Valve and Mode Valve are moved according to the position of the A/C Mode Selector. The Selector contains vacuum valves or switches. These valves apply and remove vacuum to Vacuum Actuators that move the inlet and outlet valves.
The O/S Air-Recirc. Valve is in position A for every A/C Mode Selector position except MAX. The actuator bellows are expanded which opens the O/S Air-Recirc. Valve and lets outside air into the module.
When the A/C Mode Selector is moved to MAX, vacuum is applied to the O/S Air- Recirc. Valve Vacuum Actuator. The bellows are drawn in and the Valve is moved to position B. Air from inside the vehicle is pulled into the module.
The Heater-A/C Bi-Level Valve Vacuum Actuator, which controls the Mode Valve, can assume three positions. The Actuator is operated by two bellows and two vacuum switches. With the A/C Mode Selector in MAX, A/C, VENT or DEFROST, vacuum is applied through the WHT hose. The bellows closest to the WHT hose contract, moving the Valve to position A. Air flow is directed toward the windshield outlets or A/C-instrument panel outlets and no air flows from the floor outlets
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.
