GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Has the HVAC Blower Controls System Check been performed?

--

Go to Step 2

Go to HVAC Blower Controls System Check

2

  1. Remove the auxiliary blower motor relay, low.
  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, low. Refer to Blower Motor Relay Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

4

  1. Remove the auxiliary HVAC control modules, front and rear.
  2. Connect a J 39200 (continuity) between pins C and E of both switches.
  3. Rotate the switch to Low.

Is continuity present?

--

Go to Step 6

Go to Step 5

5

Replace the auxiliary HVAC control module. Refer to the following:

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

6

  1. Remove the auxiliary blower resistor connector.
  2. Connect a J 39200 (continuity) between pins C 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 HVAC Blower Controls System Check

--

8

Connect a J 39200 (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, low and splice S401. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

10

Locate and repair the open in CKT 1926 (DK BLU) between the auxiliary blower motor relay, low and the auxiliary HVAC control modules, front and rear. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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