GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the sunload temperature sensor harness connector.
  2. Turn the ignition switch to the RUN position.
  3. Place the heater-A/C control in the AUTO position.
  4. Use a digital multimeter (DMM) in order to measure the voltage between the sun load temperature sensor harness connector terminal A (circuit 590) and ground.

Is the measured voltage within the specified range?

4-6 V

Go to Step 2

Go to Step 3

2

Use a DMM in order to measure the voltage between the sun load temperature sensor harness connector terminal A (circuit 590) and terminal B (circuit 61).

Is the measured voltage within the specified range?

4-6 V

Go to Step 4

Go to Step 5

3

Locate and repair a poor connection or an open in circuit 590 (LT BLU/BLK) between the sun load temperature sensor harness connector terminal A and the heater-A/C control harness connector terminal C2.

Is the repair complete?

--

Go to Step 6

--

4

Replace the sun load temperature sensor. Refer to Sun Load Sensor Replacement .

Is the repair complete?

--

Go to Step 6

--

5

Locate and repair a poor connection or an open in circuit 61 (YEL) between the sun load temperature sensor harness connector terminal B and splice S 258.

Is the repair complete?

--

Go to Step 6

--

6

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

Is the repair complete?

--

Go to Step 6

--

7

Verify that the systems operate properly.

Does the system operate properly?

--

System OK

Go to Diagnostic System Check