GM Service Manual Online
For 1990-2009 cars only
Table 1: Reference Table

Reference Table

Symptom

Causes

Blower motor inoperative in Low speed only

    • An open in the blower motor resistor ground circuit--Refer to Circuit Testing and Wiring Repairs .
    • A faulty blower motor resistor--Test the blower motor resistor for an open. Refer to Circuit Testing and Blower Motor Resistor Replacement .

Blower motor inoperative in High speed only

    • An open in the blower motor ground circuit between S223 and the blower switch--Refer to Circuit Testing and Wiring Repairs .
    • A faulty blower switch--Test the blower switch for high resistance or for an open in the high position. Refer to Circuit Testing and Blower Switch Replacement .

Blower motor operates at High speed only

    • An open between S223 and the blower motor resistor--Refer to Circuit Testing and Wiring Repairs .
    • A faulty blower switch--Test the blower switch for an open. Refer to Circuit Testing and Blower Switch Replacement .
    • A faulty blower motor resistor--Test the blower motor resistor for an open. Refer to Circuit Testing and Blower Motor Resistor Replacement .

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: Blower motor inoperative in Medium 1 or Medium 2.

1

Did you review the Air Delivery Description and Operation and the Air Temperature Description and Operation perform the necessary inspections?

Go to Step  2

Go to Symptoms - HVAC Systems - Manual

2

Operate the blower motor at each speed.

Is the blower motor inoperative in one speed only?

Go to Step  3

Go to Testing for Intermittent Conditions and Poor Connections

3

Test the blower motor speed circuit for an open in the affected speed. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step  8

Go to Step  4

4

Test the blower motor resistor for an open in the affected speed. Refer to Circuit Testing and Wiring Repairs .

Did the blower motor resistor test OK?

Go to Step  5

Go to Step  6

5

Inspect for a poor connection at the harness connector of the blower switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 8

Go to Step  7

6

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

Did you complete the replacement?

Go to Step  8

--

7

Replace the blower switch. Refer to Blower Switch Replacement .

Did you complete the replacement?

Go to Step 8

--

8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3