GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Has the Heater Blower Controls System Check been performed?

--

Go to Step 2

Go to Heater Blower Controls System Check

2

  1. Remove the Auxiliary Blower Motor Relay, Medium.
  2. Connect a fused jumper wire between cavities 1 and 4 of the relay socket.

Does the blower motor run?

--

Go to Step 3

Go to Step 4

3

Replace the Auxiliary Blower Motor Relay, Medium. Refer to Blower Motor Relay Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

4

  1. Remove the Auxiliary HVAC Control Module, Front.
  2. Connect a DMM (continuity) between pins B and F of the switch.
  3. Rotate the switch to Med.

Is continuity present?

--

Go to Step 6

Go to Step 5

5

Replace the Auxiliary HVAC Control Module, Front. Refer to Control Switch Replacement - Auxiliary .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

6

  1. Remove the Auxiliary Blower Resistor connector.
  2. Connect a DMM (continuity) between pins A and B of the resistors connector.

Is continuity present?

--

Go to Step 8

Go to Step 7

7

Replace the Auxiliary Blower Resistor. Refer to Auxiliary Blower Motor Resistor Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

8

Connect a DMM (volts) between cavity 1 of the high relay socket and ground.

Is battery voltage present?

--

Go to Step 10

Go to Step 9

9

Locate and repair the open in CKT 542 (RED) between cavity 1 of the Auxiliary Blower Relay, Medium and splice S401. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

10

Locate and repair the open in CKT 1925 (RED) between the Auxiliary Blower Motor Relay, Medium and the Auxiliary HVAC Control Module, Front. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Heater Blower Controls System Check

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