GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Use a test lamp, connected to B+, in order to backprobe the heater-A/C control harness connector terminal D 1 (circuit 61)

Does the test lamp light?

--

Go to Step 3

Go to Step 2

2

Locate and repair a poor connection, or an open in circuit 61 (YEL) between the heater-A/C control harness connector terminal D 1 and S 258.

Is the repair complete?

--

Go to Step 4

--

3

Replace the heater-A/C control. Refer to Control Assembly Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Step 4

--

4

Verify that the systems operates properly.

Does the system operate properly?

--

System OK

Go to Diagnostic System Check