GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The blower does not operate in any mode.

1

  1. Disconnect the blower control module.
  2. Turn the ignition to RUN.
  3. Measure voltage between terminal B of the blower control module and ground.

Is voltage greater than the specified value?

10.5 V

Go to Step 2

Go to Step 7

2

Ignition OFF, measure resistance of CKT 350 (BLK).

Is resistance measured within the specified range?

0 ohms

Go to Step 3

Go to Step 8

3

  1. Set the blower speed control to LO.
  2. Measure voltage between terminal C of the blower control module and ground.

Is votlage measured greater than the value?

9 V

Go to Go to Step 4

Go to Step 5

4

  1. Set the blower speed control to HI.
  2. Measure voltage between terminal C of the blower control module and ground.

Is the voltage measured less than the value?

3 V

Go to Step 6

Go to Step 5

5

Inspect CKT 754(GRY/BLK) for a short to ground.

Was a short condition repaired in CKT 754(GRY/BLK)?

--

Go to Step 12

Go to Step 9

6

Measure voltage between terminals A and B of the blower motor.

Is the votlage measured greater than the value?

10.5 V

Go to Step 10

Go to Step 11

7

Inspect CKT 1340 (ORN) for an open or a short to ground.

Was a wiring fault located and repaired on CKT 1340 (ORN)?

--

Go to Step 12

--

8

Repair the wire fault in the CKT 350 (BLK) between the blower control module and blower motor.

Is the repair complete?

--

Go to Step 12

--

9

Replace the instrument panel intergration module. Refer to Body Control Module Replacement

Is the repair complete?

--

Go to Step 12

--

10

Replace the blower motor. Refer to Blower Motor and Fan Replacement

Is the repair complete?

--

Go to Step 12

--

11

Replace the blower control module. Refer to Blower Motor Control Module Replacement

Is the repair complete?

--

Go to Step 12

--

12

Confirm proper operation of the blower motor.

Is the blower motor operating correctly?

--

System OK

--