GM Service Manual Online
For 1990-2009 cars only

Blower Motor Low and Medium Speeds Inoperative

Step

Action

Value(s)

Yes

No

1

  1. Place the ignition switch in the RUN position.
  2. Place the HVAC selector in the vent position.
  3. Place the blower switch in the LO position.
  4. With a digital multimeter, measure the voltage between the blower motor relay connector cavity 87A and ground.

Is the voltage greater than the specified value?

4 V

Go to Step 2

Go to Step 5

2

Check for a poor connection at the blower motor relay.

Was a poor connection found?

--

Go to Step 3

Go to Step 4

3

Repair the bad connection at the blower motor relay.

Is the repair complete?

--

System OK

--

4

Replace the blower motor relay.

Is the repair complete?

--

System OK

--

5

  1. Disconnect the connector at the blower motor resistor.
  2. Connect a self-powered test lamp between the blower motor resistor connector cavity C and the high blower motor relay socket cavity 87A.

Does the test lamp light.

--

Go to Step 6

Go to Step 7

6

Replace the blower motor resistor.

Is the repair complete?

--

System OK

--

7

Repair the open in the CKT 101 (DK BLU) between the blower resistor and the high blower motor relay.

Is the repair complete?

--

System OK

--