GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the entire HVAC System Check performed?

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Go to Step 2

Go to HVAC System Check

2

  1. Place the ignition switch in the RUN position.
  2. With a test light, backprobe the auxiliary heater-A/C control between connector C1 terminal 1 and ground.

Is the test light on?

--

Go to Step 3

Go to Step 4

3

With a test light, backprobe the auxiliary heater-A/C control between connector C1 terminal 1 and connector C2 terminal C.

Is the test light on?

--

Go to Step 5

Go to Step 6

4

Repair the poor connection or open in CKT 641 between the auxiliary heater-A/C control connector C1 terminal 1 and S345.

Is the repair complete?

--

Go to Step 11

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5

  1. Place the rear window wiper/washer and multi-function switch to the REAR position.
  2. Connect a test light between the auxiliary heater-A/C control connector C1 terminal 3 and B+.

Is the test light on?

--

Go to Step 7

Go to Step 8

6

Repair the poor connection or open in CKT 1750.

Is the repair complete?

--

Go to Step 11

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7

Replace the auxiliary heater-A/C control. Refer to Control Assembly Replacement - Auxiliary in Side Trim Panel or Control Assembly Replacement - Auxiliary in Overhead Console .

Is the repair complete?

--

Go to Step 11

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8

Connect the test light between the rear window wiper/washer and multi-function switch connector C2 terminal G and B+.

Is test light on?

--

Go to Step 9

Go to Step 10

9

Repair the poor connection or open in CKT 778.

Is the repair complete?

--

Go to Step 11

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10

Replace the rear window wiper/washer and multi-function switch. Refer to Auxiliary Air Conditioning (A/C) Control Assembly Replacement - Front .

Is the repair complete?

--

Go to Step 11

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11

  1. Turn the ignition switch to the OFF position.
  2. Reconnect all connectors/components removed.

Have all the repairs been made?

--

Go to HVAC System Check

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