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. Using a J 39200 , probe between the heater-A/C control connector C2 terminal G and ground.
  3. Move the temperature control knob from hot to cold, and cold to hot.

Does the measured voltage vary between approximately 1 and 12 volts?

1-12 V

Go to Step 3

Go to Step 4

3

  1. Disconnect the electric slave actuator connector.
  2. Using a J 39200 , probe between the electric slave actuator connector terminal 10 and ground.

Is the measured voltage within the specified values?

9-14 V

Go to Step 5

Go to Step 6

4

  1. Check for a poor connection at the heater-A/C control connector C2 terminal G.
  2. Check for a short to ground or voltage in CKT 733.
  3. If OK, replace the heater-A/C control. Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Step 11

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5

Using a J 39200 , backprobe the electric slave actuator connector terminals 10 and 7.

Is the measured voltage within the specified values?

9-14 V

Go to Step 7

Go to Step 8

6

Repair the poor connection or open in CKT 241 between the electric slave actuator connector terminal 10 and S264.

Is the repair complete?

--

Go to Step 11

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7

Using a J 39200 , backprobe the electric slave actuator connector terminal 8 and ground while moving the temperature control knob.

Does the measured voltage vary between approximately 1 and 12 volts?

1-12 V

Go to Step 9

Go to Step 10

8

Repair the poor connection or open in CKT 150 between the electric slave actuator connector terminal 7 and S213.

Is the repair complete?

--

Go to Step 11

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9

  1. Check for a poor connection at the electric slave actuator or a binding air temperature valve.
  2. If OK, replace the electric slave actuator. Refer to Temperature Actuator Replacement .

Is the repair complete?

--

Go to Step 11

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10

Repair the poor connection or open in CKT 733 between the electric slave actuator connector terminal 8 and the heater-A/C control connector C2 terminal G.

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?

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Go to HVAC System Check

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