GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the blower motor resistor harness connector.
  2. Turn the ignition switch to the RUN position.
  3. Place the heater-A/C control in the VENT position.
  4. Place the blower switch in the inoperative position.
  5. Use a test lamp to probe between the blower motor resistor connector terminal C (circuit 73) and ground:

Does the test lamp light ?

--

Go to Step 2

Go to Step 3

2

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

Is the repair complete?

--

System OK

--

3

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the heater-A/C control connector C 1.
  3. Inspect for a poor connection or in an open circuit 73 (PPL)

Is there a fault in the circuit?

--

Go to Step 4

Go to Step 5

4

Repair the poor connection or the open in circuit 73 (PPL).

Is the repair complete?

--

System OK

--

5

Replace the heater-A/C control. Refer to Control Assembly Replacement .

Is the repair complete?

--

System OK

--