GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Heater Blower Controls System Check performed?

--

Go to Step 2

Go to Heater Blower Controls System Check

2

  1. Disconnect the connector at the auxiliary blower motor.
  2. Disconnect the connector at the auxiliary blower motor resistor.
  3. Disconnect the connector at the auxiliary blower motor high speed relay.
  4. Disconnect the connector at the auxiliary blower motor medium speed relay.
  5. Disconnect the connector at the auxiliary blower motor low speed relay.
  6. Place the ignition switch in the RUN position.
  7. Place the auxiliary blower motor switch in the Off position.
  8. Connect an unpowered test lamp between the auxiliary blower motor connector, cavity B for CKT 1172 (YEL), and ground.

Does the test lamp light?

--

Go to Step 13

Go to Step 3

3

Connect an unpowered test lamp between the auxiliary blower motor resistor connector, cavity A for CKT 1176 (YEL), and ground.

Does the test lamp light?

--

Go to Step 14

Go to Step 4

4

Connect an unpowered test lamp between the auxiliary blower motor resistor connector, cavity C for CKT 1072 (LT BLU), and ground.

Does the test lamp light?

--

Go to Step 15

Go to Step 5

5

  1. Connect the auxiliary blower motor resistor connector.
  2. Connect the auxiliary blower motor connector.
  3. Connect the auxiliary blower motor low speed relay connector.

Does the auxiliary blower motor operate?

--

Go to Step 6

Go to Step 8

6

Disconnect the auxiliary blower motor switch connector.

Does the auxiliary blower motor cease operating?

--

Go to Step 16

Go to Step 7

7

  1. Disconnect the auxiliary blower motor low speed relay connector.
  2. Connect a J 39200 between the auxiliary blower motor low speed relay connector, cavity A1 for CKT 1926 (DK BLU), and ground.

Is continuity present?

--

Go to Step 17

Go to Step 18

8

Connect the auxiliary blower motor medium speed relay connector.

Does the auxiliary blower motor operate?

--

Go to Step 9

Go to Step 11

9

Disconnect the auxiliary blower motor switch connector.

Does the auxiliary blower motor cease operating?

--

Go to Step 16

Go to Step 10

10

  1. Disconnect the auxiliary blower motor medium speed relay connector.
  2. Connect a J 39200 between the auxiliary blower motor medium speed relay connector, cavity A1 for CKT 1925 (RED), and ground.

Is continuity present?

--

Go to Step 19

Go to Step 20

11

Disconnect the auxiliary blower motor switch connector.

Connect a J 39200 between the auxiliary blower motor switch connector, cavity D, and cavity 

Is continuity present?

--

Go to Step 21

Go to Step 12

12

Connect a J 39200 between the auxiliary blower motor switch, pin D, and pin B.

Is continuity present?

--

Go to Step 16

Go to Step 22

13

Repair the short to voltage in CKT 1172 (YEL) between the following components:

    â€¢ The auxiliary blower motor resistor connector.
    â€¢ The auxiliary blower motor high speed relay connector.
    â€¢ The auxiliary blower motor connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

14

Repair the short to voltage in CKT 1176 (YEL) between the auxiliary blower motor resistor connector and the auxiliary blower motor low speed relay connector:

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

15

Repair the short to voltage in CKT 1072 (LT BLU) between the auxiliary blower motor resistor connector and the auxiliary blower motor medium speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

16

Replace the auxiliary blower motor switch.

Refer to one of the following procedures:

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

17

Repair the short to ground in CKT 60 (YEL) / 1926 (DK BLU) between the auxiliary blower motor switch connector and the auxiliary blower motor low speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

18

Replace the auxiliary blower motor low speed relay.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

19

Repair the short to ground in CKT 63 (TAN) / 1925 (RED) between the auxiliary blower motor switch connector and the auxiliary blower motor medium speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

20

Replace the auxiliary blower motor medium speed relay.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

21

Repair the short to ground in CKT 52 (ORN ) / 1924 (WHT) between the auxiliary blower motor switch connector and the auxiliary blower motor high speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

22

Replace the auxiliary blower motor high speed relay.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--