GM Service Manual Online
For 1990-2009 cars only

Auxiliary Blower Motor Inoperative at Any Speed Cargo Van

Step

Action

Value(s)

Yes

No

1

Was the HVAC Blower Controls System Check performed?

--

Go to Step 2

Go to HVAC Blower Controls System Check

2

  1. Disconnect the auxiliary blower motor low speed relay connector.
  2. Connect an unpowered test lamp between the auxiliary blower motor low 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 low speed relay connector, cavity C1 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 front auxiliary HVAC control module.
  2. Connect a J 39200 between the front auxiliary HVAC control module connector, cavity F for CKT 150 (BLK), and ground.

Is continuity present?

--

Go to Step 5

Go to Step 10

5

  1. Place the front auxiliary HVAC control module in the LOW position.
  2. Connect a J 39200 between the front auxiliary HVAC control module, pin C and pin F.

Is continuity present?

--

Go to Step 6

Go to Step 11

6

  1. Disconnect the connector at the auxiliary blower motor.
  2. Connect a J 39200 between the auxiliary blower motor connector, cavity A for CKT 150 (BLK), and ground.

Is continuity present?

--

Go to Step 7

Go to Step 12

7

  1. Disconnect the connector at the auxiliary blower motor resistor.
  2. Connect a J 39200 between the auxiliary blower motor resistor connector, cavity D, and the auxiliary blower motor connector, cavity B for CKT 1172 (YEL).

Is continuity present?

--

Go to Step 13

Go to Step 14

8

Repair the open in CKT 1542 (RED) between the underhood fuse-relay center and splice S412.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

9

Repair the open in CKT 341 (BRN) between the instrument panel fuse block and splice S405.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

10

Repair the open in CKT 150 (BLK) between the front auxiliary HVAC control module and ground G400.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

11

Replace the front auxiliary HVAC control module.

Refer to Control Switch Replacement - Auxiliary .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

12

Repair the open in CKT 150 (BLK) between the auxiliary blower motor and ground G400.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

13

Replace the auxiliary blower motor.

Refer to Auxiliary Blower Motor Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

14

Repair the open in CKT 1172 (YEL) between splice S413 and the auxiliary blower motor.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

Auxiliary Blower Motor Inoperative at Any Speed Passenger Van

Step

Action

Value(s)

Yes

No

1

Was the HVAC Blower Controls System Check performed?

--

Go to Step 2

Go to HVAC Blower Controls System Check

2

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

Does the test lamp light?

--

Go to Step 3

Go to Step 13

3

  1. Place the ignition switch in the RUN position.
  2. Connect an unpowered test lamp between the auxiliary blower motor low speed relay connector, cavity C1 for CKT 341 (BRN), and ground.

Does the test lamp light?

--

Go to Step 4

Go to Step 14

4

  1. Disconnect the connector at the front auxiliary HVAC control module.
  2. Connect an unpowered test lamp between the front auxiliary HVAC control module connector, cavity B for CKT 150 (BLK), and ground.

Does the test lamp light?

--

Go to Step 5

Go to Step 15

5

Does the auxiliary blower motor operate when controlled by the rear auxiliary HVAC control module?

--

Go to Step 6

Go to Step 9

6

  1. Place the front auxiliary HVAC control module in the LOW position.
  2. Connect a J 39200 between the front auxiliary HVAC control module, pin C and pin B.

Is continuity present?

--

Go to Step 7

Go to Step 16

7

  1. Disconnect the auxiliary blower motor connector.
  2. Connect a J 39200 between the auxiliary blower motor connector, cavity A for CKT 150 (BLK), and ground.

Is continuity present?

--

Go to Step 8

Go to Step 17

8

  1. Disconnect the auxiliary blower motor resistor connector .
  2. Connect a J 39200 between the auxiliary blower motor resistor connector, cavity D, and the auxiliary blower motor connector, cavity B for CKT 1172 (YEL).

Is continuity present?

--

Go to Step 18

Go to Step 19

9

  1. Place the front auxiliary HVAC control module in the REAR CNTL position.
  2. Connect a J 39200 between the front HVAC control module pin B, and pin F.

Is continuity present?

--

Go to Step 10

Go to Step 16

10

  1. Disconnect the heater and A/C control logic module connector.
  2. Connect a J 39200 between the front auxiliary HVAC control module connector, cavity F and the heater and A/C control logic module connector, cavity M, for CKT 203 (LT BLU).

Is continuity present?

--

Go to Step 11

Go to Step 20

11

  1. Connect a J 39200 between the heater and A/C control logic module, pin M and pin L.
  2. Use diode test setting on the J 39200 .
  3. Observe reading of the J 39200 .
  4. Switch the position of the J 39200 leads on the heater and A/C control module.
  5. Observe reading of J 39200 .

Did the diode test good?

--

Go to Step 12

Go to Step 21

12

  1. Place the rear auxiliary HVAC control modulein the LOW position.
  2. Disconnect the rear auxiliary HVAC control module connector.
  3. Connect a J 39200 between the rear auxiliary HVAC control module, pin C and pin F.

Is continuity present?

--

Go to Step 22

Go to Step 23

13

Repair the open in CKT 1542 (RED) between the underhood fuse-relay center and splice S412.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

14

Repair the open in CKT 341 (BRN) between the instrument panel fuse block and splice S405.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

15

Repair the open in CKT 150 (BLK) between the front auxiliary HVAC control module connector and ground G400.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

16

Replace the front auxiliary HVAC control module.

Refer to Control Switch Replacement - Auxiliary .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

17

Repair the open in CKT 150 (BLK) between the auxiliary blower motor connector and ground G400.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

18

Replace the auxiliary blower motor.

Refer to Auxiliary Heater Core Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

19

Repair the open in CKT 1172 (YEL) between splice S413 and the auxiliary blower motor.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

20

Repair the open in CKT 203 (LT BLU) between the front auxiliary NVAC control module connector and the heater and A/C control logic module connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

21

Replace the heater and A/C control logic module.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

22

Repair the open in CKT 77 (DK BLU between the heater and A/C control logic module connector and the rear auxiliary HVAC control module connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

23

Replace the rear auxiliary HVAC control module.

Refer to Control Switch Replacement - Auxiliary .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--