Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

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

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

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 any of the speed positions?

Go to Blower Motor Malfunction

Go to Step 3

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

Does the test lamp illuminate?

Go to Step 14

Go to Step 4

Probe the supply voltage circuit of the blower motor with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 5

1. Turn OFF the ignition.
2. Remove the blower motor relay.
3. Test the battery positive voltage circuit on the switch side and the coil side of the relay connector with a test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 17

1. Turn ON the ignition with the engine OFF.
2. Turn ON the HVAC control module.
3. Probe the blower motor relay control circuit with a test lamp that is connected to voltage.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

Test the blower motor supply voltage circuit for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 13

Test the blower motor relay control circuit for an open, short to voltage or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 16

1. Turn OFF the ignition.
2. Disconnect the blower motor control processor.
3. Turn ON the ignition.
4. Place the blower switch on high speed.
5. Probe the blower motor speed control circuit with a test lamp connected to battery voltage.

Does the test lamp illuminate?

Go to Step 11

Go to Step 10

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

Did you find and correct the condition?

Go to Step 22

Go to Step 16

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 22

Go to Step 12

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

Did you find and correct the condition?

Go to Step 22

Go to Step 15

Inspect for poor connections at the harness connector of the blower motor relay. 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 22

Go to Step 18

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 22

Go to Step 19

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.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

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 22

Go to Step 21

Repair the battery positive voltage circuit of the blower motor relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

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Replace the blower motor relay.

Did you complete the replacement?

Go to Step 22

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

Did you complete the replacement?

Go to Step 22

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

Did you complete the replacement?

Go to Step 22

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Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

Go to Step 22

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2