GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you review the Control Assembly Description and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms

2

Verify that the RH temperature control actuator motor is inoperative.

Does the system operate normally?

--

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

Go to Step 3

3

  1. Turn the ignition switch On, with the engine OFF.
  2. Disconnect the RH temperature control actuator motor harness connector.
  3. Connect a Digital Multi Meter (DMM) to measure the voltage on the RH temperature control actuator motor signal circuit.
  4. Move the temperature control from Hot to Cold and from Cold to Hot.

Does the measured voltage vary within the specified range with the movement of the temperature control ?

1-12V

Go to Step 4

Go to Step 5

4

  1. Keep the ignition switch in the ON position.
  2. Use DMM to test for B+ on the ignition positive voltage circuit of the RH temperature control actuator motor.

Is the measured voltage within the specified value?

9-14V

Go to Step 6

Go to Step 7

5

Test for a loose connection or an open on the RH temperature control actuator motor signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

6

  1. Keep the ignition switch in the ON position.
  2. Connect a DMM between the ignition positive voltage circuit of the RH temperature control actuator motor and the temperature control actuator motor ground circuit.

Is the measured voltage within the specified value?

9-14V

Go to Step 8

Go to Step 10

7

Test for a loose connection or an open on the ignition positive voltage circuit of the RH temperature control actuator motor . Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

--

8

Replace the RH temperature control actuator motor. Refer to Temperature Actuator Replacement .

Is the repair complete?

--

Go to Step 11

--

9

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

Is the repair complete?

--

Go to Step 11

--

10

Test for a loose connection or an open in the RH temperature control actuator motor ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Symptoms