GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The front blower motor will not operate in LO speed only.

1

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

 

Go to Step 2

Go to Symptoms

2

  1. Place the ignition switch in the RUN position.
  2. Place the heater and A/C controller mode switch in the Heat position.
  3. Place the heater and A/C controller blower motor switch in the LO position.

Does the blower motor operate?

--

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

Go to Step 3

3

  1. Disconnect the blower motor resistor/relay connector.
  2. Connect a J 35616-200 unpowered test lamp between blower motor resistor/relay connector cavity E for CKT 60 (YEL) and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 4

4

  1. Disconnect heater and A/C controller connector C2.
  2. Connect a J 39200 digital multimeter (DMM) between heater and A/C controller pin A and pin G. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

--

Go to Step 5

Go to Step 7

5

Repair the open in CKT 60 (YEL) between the heater and A/C controller connector and the blower motor resistor/relay connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 8

--

6

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

Did you complete the repair?

--

Go to Step 8

--

7

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

Did you complete the repair?

--

Go to Step 8

--

8

Operate the blower motor in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3