GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Bonneville 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Blower Motor Inoperative

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for blower motor operation in any speed setting.

    2.

  2. This step determines if the instrument panel integration module (IPM) is receiving a blower speed request from the HVAC control module and commanding an output.

    3.

  3. This step tests for an open or poor connection at the blower motor control processor.

    4.

  4. This step tests for an open or poor connection at the IPM.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The blower motor is inoperative in all speed positions.

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the blower motor switch in each speed position.

Does the blower motor operate in the desired speeds?

--

Go to Blower Motor Malfunction

Go to Step 3

3

  1. Place the blower motor switch in the maximum speed position.
  2. With the scan tool, observe the Commanded Blower parameter in the Instrument Panel Module data list.

Does the scan tool indicate that the Commanded Blower parameter is near the specified value?

100%

Go to Step 5

Go to Step 4

4
  1. With the scan tool, command the blower motor ON.
  2. Observe the Commanded Blower parameter.

Does the scan tool indicate that the Commanded Blower parameter is near the specified value?

100%

Go to Step 13

Go to Step 14

5
  1. Turn OFF the ignition.
  2. Disconnect the blower motor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the blower motor supply voltage circuit and the blower motor control circuit.
  5. Place the blower motor switch in the minimum speed position.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 6

6

Test the battery positive voltage circuit of the blower motor control processor for an open, a high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 7

7

Test the ground circuit of the blower motor control processor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 8

8

Important: Ensure that the blower motor control processor module and the instrument panel integration module (IPM) control assembly connectors are connected during this step in order to avoid misdiagnosis.

  1. Measure the voltage from the blower motor speed control circuit of the IPM to a good ground.
  2. With a scan tool, command the blower motor OFF and ON.

Does the voltage measure near the specified values for each commanded state?

5 V OFF

1.5 V ON

Go to Step 12

Go to Step 9

9

  1. Turn OFF the ignition.
  2. Disconnect the IPM.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the blower motor speed control circuit of the IPM to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 14

Go to Step 10

10

Test the blower motor speed control circuit of the IPM for an open, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 12

11

Inspect for poor connections at the harness connector of the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 15

12
  1. Inspect for poor connections at the harness connector of the blower motor control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
  2. Visually inspect the harness

Did you find and correct the condition?

--

Go to Step 19

Go to Step 16

13

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

14

Inspect for poor connections at the harness connector of the IPM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 18

15

Replace the blower motor. Refer to Blower Motor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 19

--

16

Replace the blower motor control processor. Refer to Blower Motor Control Processor Replacement .

Did you complete the replacement?

--

Go to Step 19

--

17

Replace the HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 19

--

18

Replace the IPM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2