Schematic Reference: HVAC Schematics

DEFINITION: The auxiliary 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 - Manual

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

Does the auxiliary blower motor operate in any speed position?

Go to Blower Motor Malfunction

Go to Step 3

1. Turn OFF the ignition.
2. Disconnect the auxiliary blower motor.
3. Turn ON the ignition, with the engine OFF.
4. Probe the ignition 3 voltage circuit of the auxiliary blower motor with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 11

1. Place the front auxiliary blower motor switch in the maximum speed position.
2. Connect a test lamp between the ignition 3 voltage circuit and the auxiliary blower motor speed control circuit of the auxiliary blower motor.

Does the test lamp illuminate?

Go to Step 10

Go to Step 5

Important: The front auxiliary blower motor switch must remain in the maximum speed position during this step.

1. Turn OFF the ignition.
2. Disconnect the auxiliary blower motor relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the ignition 3 voltage circuit and the high blower motor control circuit of the auxiliary blower motor relay.

Does the test lamp illuminate?

Go to Step 6

Go to Step 7

Test the auxiliary blower motor speed control circuit of the auxiliary blower motor 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 15

Go to Step 8

Test the ground circuit of the front auxiliary blower motor switch 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 15

Go to Step 9

Inspect for poor connections at the harness connector of the auxiliary 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 15

Go to Step 12

Inspect for poor connections at the harness connector of the front auxiliary blower motor switch. 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 15

Go to Step 13

Inspect for poor connections at the harness connector of the auxiliary 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 15

Go to Step 14

Repair the ignition 3 voltage circuit of the auxiliary blower motor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 15

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Replace the auxiliary blower motor relay.

Did you complete the replacement?

Go to Step 15

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Replace the front auxiliary blower motor switch. Refer to Auxiliary Blower Motor Switch Replacement .

Did you complete the replacement?

Go to Step 15

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Replace the auxiliary blower motor. Refer to Auxiliary Blower Motor Replacement .

Did you complete the replacement?

Go to Step 15

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3