GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you review the HVAC system operation and perform the necessary inspections?

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Go to Step 2

Go to Symptoms

2

Verify that the blower motor Med-1 speed is inoperative.

Does the blower motor operate normally?

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Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Disconnect the blower motor resistor.
  2. Connect a test lamp between CKT 63 (TAN) and ground.
  3. Turn the ignition switch to the ON position.
  4. Turn the engine OFF.
  5. Turn the mode selector switch to the HEAT position.
  6. Turn the blower switch to the MED-1 position.

Does the test lamp light?

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Go to Step 5

Go to Step 4

4

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

Is the replacement complete?

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Go to Step 8

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5

Connect a test lamp between CKT 63 (TAN) cavity at the heater and A/C controller connector C4 and ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 7

6

Repair the open in CKT 63 (TAN).

Is the repair complete?

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Go to Step 8

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7

Replace the heater and A/C controller. Refer to Control Assembly Replacement .

Is the replacement complete?

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Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3