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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Express 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Auxiliary Blower Motor Always On

Auxiliary Blower Motor Always On 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. Place the front auxiliary HVAC control module in the OFF position.
  2. Disconnect the connectors at the following components:
    3. • The auxiliary blower motor.
    • The auxiliary blower motor resistor.
    • The auxiliary blower motor high speed relay.
    • The auxiliary blower motor medium speed relay.
    • The auxiliary blower motor low speed relay.
  3. Place the ignition switch in the RUN position.
  4. 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, 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 front auxiliary HVAC control module.

Does the auxiliary blower motor cease operating?

--

Go to Step 16

Go to Step 7

7
  1. Disconnect the auxiliary blower motor 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 front auxiliary HVAC control module 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 front auxiliary HVAC control module.

Connect a J 39200 between the front auxiliary HVAC module connector, cavity D, and cavity F.

Is continuity present?

--

Go to Step 21

Go to Step 12

12

Connect a J 39200 between the front auxiliary HVAC control module, pin D, and pin F.

Is continuity present?

--

Go to Step 16

Go to Step 22

13

Repair the short to voltage in CKT 1172 (YEL) between the auxiliary blower motor connector, auxiliary blower motor resistor connector, and the auxiliary blower motor high speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC 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 HVAC 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 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 short to ground in CKT 1926 (DK BLU)/CKT 60 (YEL) between the front auxiliary HVAC control module connector and the auxiliary blower motor low speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

18

Replace the auxiliary blower motor low speed relay.

Isthe repair complete?

--

Go to HVAC Blower Controls System Check

--

19

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

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

20

Replace the auxiliary blower motor medium speed relay.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

21

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

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

22

Replace the auxiliary blower motor high speed relay.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

Auxiliary Blower Motor Always On 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. Place the front auxiliary HVAC control module in the OFF position.
  2. Place the rear auxiliary HVAC control module in the OFF position.
  3. Disconnect the connectors at the following components:
    4. • The auxiliary blower motor
    • The auxiliary blower motor resistor
    • The auxiliary blower motor high speed relay
    • The auxiliary blower motor medium speed relay
    • The auxiliary blower motor low speed relay
  4. Place the ignition switch in the RUN position.
  5. 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 15

Go to Step 3

3

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

Does the test lamp light?

--

Go to Step 16

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 17

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 9

6

Disconnect the front auxiliary HVAC control module connector.

Does the auxiliary blower motor cease operating?

--

Go to Step 18

Go to Step 7

7

Disconnect the rear auxiliary HVAC control module connector.

Does the auxiliary blower motor cease operating?

--

Go to Step 19

Go to Step 8

8
  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 20

Go to Step 21

9

Connect the auxiliary blower motor medium speed relay connector.

Does the auxiliary blower motor operate?

--

Go to Step 10

Go to Step 13

10

Disconnect the front auxiliary HVAC control module connector.

Does the auxiliary blower motor cease operating?

--

Go to Step 18

Go to Step 11

11

Disconnect the rear auxiliary HVAC control module connector.

Does the auxiliary blower motor cease operating?

--

Go to Step 19

Go to Step 12

12
  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 22

Go to Step 23

13
  1. Disconnect the front auxiliary HVAC control module connector.
  2. Connect a J 39200 between the front HVAC control module connector, cavity D, and cavity B.

Is continuity present?

--

Go to Step 14

Go to Step 18

14
  1. Disconnect the rear auxiliary HVAC control module connector.
  2. Connect a J 39200 between the rear HVAC control module connector, cavity D, and cavity B.

Is continuity present?

--

Go to Step 24

Go to Step 25

15

Repair the short to voltage in CKT 1172 (YEL) between the auxiliary blower motor connector, auxiliary blower motor resistor connector, and the auxiliary blower motor high speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

16

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 HVAC Blower Controls System Check

--

17

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 HVAC Blower Controls System Check

--

18

Replace the front auxiliary HVAC control module.

Refer to Control Switch Replacement - Auxiliary .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

19

Replace the rear auxiliary HVAC control module.

Refer to Control Switch Replacement - Auxiliary .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

20

Repair the short to ground in CKT 1926 (DK BLU) / 60 (YEL) between the following components:

    • The front auxiliary HVAC control module connector.
    • The rear auxiliary HVAC control module connector.
    • The auxiliary blower motor low speed relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

21

Replace the auxiliary blower motor low speed relay.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

22

Repair the short to ground in CKT 1925 (RED) / 63 (TAN) between the following components:

    • The front auxiliary HVAC control module connector
    • The rear auxiliary HVAC control module connector
    • The auxiliary blower motor medium speed relay connector

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

23

Replace the auxiliary blower motor medium speed relay.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

24

Repair the short to ground in CKT 1924 (WHT) / 52 (ORN) between the following components:

    • The rear auxiliary HVAC control module connector
    • The front auxiliary HVAC control module connector
    • The auxiliary blower motor high speed relay connector

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

25

Replace the auxiliary blower motor high speed relay.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--