GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to Symptoms

2

Inspect the HVAC fuse for an open.

Is the fuse open?

--

Go to Step 3

Go to Step 4

3

Locate and repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

4

  1. Disconnect the heater-A/C control connector C2.
  2. Place the ignition switch in the RUN position.
  3. Use a digital multimeter (DMM) to probe between the heater-A/C control harness connector C2 terminal C and Terminal K.

Is the measured voltage within the specified value?

B+

Go to Step 8

Go to Step 5

5

Use the DMM to probe between the heater-A/C control harness connector C2 terminal C and ground.

Is the measured voltage within the specified value?

B+

Go to Step 7

Go to Step 6

6

Locate and repair a poor connection or an open in CKT 41 (BRN) between the fuse block terminal D10 and the heater/C control harness connector C2 terminal C.. repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

7

Locate and repair a poor connection or an open in CKT 1450 (BLK) between the heater-A/C control harness connector C2 terminal K and G200. repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

8

  1. Place the ignition switch in the OFF position.
  2. Reconnect the heater-A/C control connector C2.
  3. Disconnect the left electric actuator.
  4. Place the ignition switch in the RUN position.
  5. Use a DMM to probe the left electric actuator harness connector between terminal 10 and terminal 7.

Is the measured voltage within the specified value?

B+

Go to Step 12

Go to Step 9

9

Use a DMM to probe between the left electric actuator harness connector terminal 10 and ground.

Is the measured voltage within the specified value?

B+

Go to Step 11

Go to Step 10

10

Locate and repair a poor connection or an open in CKT 41 (BRN) between splice S233 and the left electric actuator harness connector terminal 10. repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

11

Locate and repair a poor connection or an open in CKT 1450 (BLK) between the left electric actuator harness connector terminal 7 and G200. repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

12

  1. Use a DMM to probe between the left electric actuator harness connector terminal 8 and ground.
  2. Move the temperature control from HOT to COLD and COLD to HOT positions.

Is the measured voltage within the specified value?

1-12 V

Go to Step 13

Go to Step 14

13

Replace the left electric actuator. Refer to Temperature Actuator Replacement (LH) .

Is the repair complete?

--

Go to Step 19

--

14

Inspect for a short to ground or B+ in CKT 1199 (DK BLU).

Does a short exist?

--

Go to Step 15

Go to Step 16

15

Repair the short to ground or B+ in CKT 1199 (DK BLU). repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

16

Inspect for a poor connection or an open in CKT 1199 (DK BLU).

Does a poor connection or open exist?

--

Go to Step 17

Go to Step 18

17

Repair the poor connection or open in CKT 1199 (DK BLU). repair a short to ground in CKT 41 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

18

Replace the heater-A/C control. Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Step 19

--

19

Verify that the system operates properly.

Does the system operate properly?

--

System OK

Go to Symptoms