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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Blower Motor Medium Speed Inoperative - Auxiliary Air Conditioning (A/C)

Step

Action

Value(s)

Yes

No

DEFINITION:

    • The rear auxiliary blower motor MED speed will not operate from the front auxiliary HVAC control module or from the rear auxiliary HVAC control module.
    • Vehicle is equipped with rear A/C (C69).

1

Did you review the HVAC blower operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms

2
  1. Place the ignition switch in the RUN position.
  2. For cargo vehicle: Place the front auxiliary HVAC control module in the MED position.
  3. For passenger vehicle:
    4. • Place the front auxiliary HVAC control module in the MED position.
    • Place the front auxiliary HVAC control module in the REAR CNTL position and the rear auxiliary HVAC control module in the MED position.

Does the blower motor operate?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3
  1. Disconnect the auxiliary blower motor medium speed relay.
  2. Connect a J 35616-200 unpowered test lamp between auxiliary blower motor high speed relay connector cavity C1 for CKT 1542 (RED) and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 14

4

Connect a J 35616-200 unpowered test lamp between auxiliary blower motor medium speed relay connector cavity C2 for CKT 341 (BRN) and ground.

Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 15

5
  1. Disconnect the auxiliary blower motor.
  2. Connect a J 39200 digital multimeter (DMM) between auxiliary blower motor medium speed relay connector cavity A2 and auxiliary blower motor connector cavity B for CKT 1072 (YEL). Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 6

Go to Step 16

6

Is vehicle equipped with a rear HVAC control module?

--

Go to Step 9

Go to Step 7

7
  1. Place the front auxiliary HVAC control module in the MED position.
  2. Connect a J 39200 DMM between auxiliary blower motor low speed relay connector cavity A1 for CKT 1925 (RED) and ground. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 20

Go to Step 8

8
  1. Disconnect the front HVAC control module.
  2. Connect a J 39200 DMM between front HVAC control module pin E and pin F. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 17

Go to Step 21

9

Does auxiliary blower motor operate from the rear auxiliary HVAC control module?

--

Go to Step 10

Go to Step 12

10
  1. Place the front auxiliary HVAC control module in the MED position.
  2. Connect a J 39200 DMM between auxiliary blower motor medium speed relay connector cavity A1 for CKT 1925 (RED) and ground. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 20

Go to Step 11

11
  1. Disconnect the front auxiliary HVAC control module.
  2. Connect a J 39200 DMM between front auxiliary HVAC control module pin E and pin B. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 18

Go to Step 21

12
  1. Place the front auxiliary HVAC control module in the REAR CNTL position.
  2. Place the rear auxiliary HVAC control module in the MED position.
  3. Connect a J 39200 DMM between auxiliary blower motor medium speed relay connector cavity A1 for CKT 1925 (RED) and ground. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 20

Go to Step 13

13
  1. Disconnect the rear auxiliary HVAC control module.
  2. Connect a J 39200 DMM between rear auxiliary HVAC control module pin E and pin B. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 19

Go to Step 22

14

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

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

15

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

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

16

Repair the open in CKT 1072 (YEL) between splice S413 and the auxiliary blower motor medium speed relay connector.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

17

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

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

18

Repair the open in CKT 63 (TAN) between the front auxiliary HVAC control module connector and splice S321

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

19

Repair the open in CKT 63 (TAN) between the rear auxiliary HVAC control module connector and splice S321

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 23

--

20

Replace the auxiliary blower motor medium speed relay.

Did you complete the repair?

--

Go to Step 23

--

21

Replace the front auxiliary HVAC control module.

Refer to Auxiliary Air Conditioning (A/C) Control Assembly Replacement - Front .

Did you complete the repair?

--

Go to Step 23

--

22

Replace the rear auxiliary HVAC control module.

Refer to Control Assembly Replacement - Auxiliary in Overhead Console .

Did you complete the repair?

--

Go to Step 23

--

23

Operate the auxiliary blower motor in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3