Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The auxiliary blower motor is on while the auxiliary blower motor switch is in the OFF position.

Did you review the auxiliary HVAC operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2

1. Turn ON the ignition, with the engine OFF.
2. Place the front auxiliary blower motor switch to the OFF position.
3. Place the rear auxiliary blower motor switch to the OFF position.

Does the auxiliary blower motor operate?

Go to Step 4

Go to Step 3

3

Important: The front auxiliary blower motor switch must remain in the OFF position.

Place the rear auxiliary blower motor switch to the maximum speed position.

Does the auxiliary blower motor operate?

Go to Step 8

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

1. Turn OFF the ignition.
2. Disconnect the rear auxiliary HVAC control assembly.
3. Turn ON the ignition, with the engine OFF.

Does the auxiliary blower motor continue to operate?

Go to Step 5

Go to Step 6

Test each auxiliary blower motor speed control circuit between the auxiliary blower motor resistor assembly and the rear auxiliary HVAC control assembly for a 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 11

1. Turn OFF the ignition.
2. Connect the rear auxiliary HVAC control assembly.
3. Disconnect the front auxiliary HVAC control assembly.
4. Turn ON the ignition, with the engine OFF.

Does the auxiliary blower motor operate?

Go to Step 7

Go to Step 13

Test each auxiliary blower motor speed control circuit between the front auxiliary HVAC control assembly and the rear auxiliary HVAC control assembly for a 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 12

1. Turn OFF the ignition.
2. Disconnect the front auxiliary HVAC control assembly.
3. Turn ON the ignition, with the engine OFF.

Does the auxiliary blower motor continue to operate?

Go to Step 9

Go to Step 13

Test the rear auxiliary enable control circuit for a 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 10

Test auxiliary blower motor control circuit for a 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 14

Inspect for poor connections at the harness connector of the auxiliary blower motor resistor assembly. 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 16

Inspect for poor connections at the harness connector of the rear auxiliary HVAC control assembly. 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

Inspect for poor connections at the harness connector of the front auxiliary HVAC control assembly. 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

Inspect for poor connections at the harness connector of the auxiliary HVAC 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 19

Go to Step 18

Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front .

Did you complete the replacement?

Go to Step 19

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Replace the auxiliary blower motor resistor assembly. Refer to Auxiliary Blower Motor Resistor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

Go to Step 19

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Replace the rear auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Rear .

Did you complete the replacement?

Go to Step 19

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Replace the auxiliary HVAC control processor. Refer to Auxiliary HVAC Control Processor Replacement .

Did you complete the replacement?

Go to Step 19

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2