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 auxiliary blower motor medium speed relay connector.
  2. Connect an unpowered test lamp between the auxiliary blower motor medium speed relay connector, cavity C1 for CKT 1542 (RED), and ground.

Does the test lamp light?

--

Go to Step 3

Go to Step 8

3

  1. Place the ignition switch in the RUN position.
  2. Connect an unpowered test lamp between the auxiliary blower motor medium speed relay connector, cavity C2 for CKT 341 (BRN), and ground.

Does the test lamp light?

--

Go to Step 4

Go to Step 9

4

  1. Disconnect the connector at the auxiliary blower motor resistor.
  2. Connect a J 39200 between the auxiliary blower motor medium speed relay connector, cavity A2, and the auxiliary blower motor resistor connector, cavity C for CKT 1072 (LT BLU).

Is continuity present?

--

Go to Step 5

Go to Step 10

5

Connect a J 39200 between the auxiliary blower motor resistor, pin C and pin D.

Is continuity present?

--

Go to Step 6

Go to Step 11

6

  1. Place the auxiliary blower motor switch in the medium position.
  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 12

Go to Step 7

7

  1. Disconnect the connector at the auxiliary blower motor switch.
  2. Connect a J 39200 between the auxiliary blower motor switch pin F, and pin B.

Is continuity present?

--

Go to Step 13

Go to Step 14

8

Repair the open in CKT 1542 (RED) between splice S412, and the auxiliary blower motor medium speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

9

Repair the open in CKT 341 (BRN) between splice S405 and the auxiliary blower motor medium speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

10

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

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

11

Replace the auxiliary blower motor resistor.

Refer to Auxiliary Blower Motor Resistor Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

12

Replace the auxiliary blower motor medium speed relay.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

13

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

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

14

Replace the auxiliary blower motor switch.

Refer to one of the following procedures:

Is the repair complete?

--

Go to Heater Blower Controls System Check

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