GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Heater Blower Controls System Check performed?

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Go to Step 2

Go to Heater Blower Controls System Check

2

  1. Disconnect the blower motor resistor.
  2. Connect a test lamp between CKT 72 (LT BLU) and ground.
  3. Turn the ignition switch to the RUN position.
  4. Turn the mode selector switch to the HEAT position.
  5. Turn the blower switch to the MED-2 position.

Does the test lamp light?

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Go to Step 4

Go to Step 3

3

Replace the blower motor resistor. Refer to Blower Motor Resistor Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

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4

Connect a test lamp between CKT 72 (LT BLU) cavity B at the HVAC control connector C4 and ground.

Does the test lamp light?

--

Go to Step 5

Go to Step 6

5

Locate and repair the open in CKT 72 (LT BLU).

Is the repair complete?

--

Go to Heater Blower Controls System Check

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6

Replace the HVAC controller. Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

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