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. Disconnect the Auxiliary Blower Resistor.
  2. Connect a jumper wire between cavities A and B of the resistor connector.
  3. Rotate the Auxiliary HVAC Control Module switch to the Med position.

Does the Auxiliary Blower Motor spin?

--

Go to Step 3

Go to Step 4

3

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

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

4

  1. Disconnect the Auxiliary Blower Motor.
  2. Connect a DMM (continuity) between cavity B of the resistor connector and cavity A of the blower connector.

Is continuity present?

--

Go to Step 6

Go to Step 5

5

Locate and repair the open in CKT 1172 (YEL) between the resistor connector and splice S402. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

6

  1. Remove the Auxiliary HVAC Control Module Front switch.
  2. Connect a DMM (continuity) between cavities B and E with switch in Low, and cavities B and F with switch in Med.

Is continuity present in both positions?

--

Go to Step 8

Go to Step 7

7

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

Is the repair complete?

Go to Heater Blower Controls System Check

--

8

  1. Connect all disconnect components test to this point.
  2. Remove both the Low and Medium Auxiliary Blower Motor Relays.
  3. Connect a fused jumper wire between cavities 5 and 2 of both socket relays with the blower switch in Low and Med.

Does the Auxiliary Blower Motor operate in both positions?

--

Go to Step 9

Go to Step 10

9

Replace both Auxiliary Blower Motor Relays. Refer to Blower Motor Relay Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

10

Locate and repair the open the circuit(s) between cavity 2 of the relay socket and the Auxiliary HVAC Control Module, Front switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Heater Blower Controls System Check

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