Schematic Reference: HVAC Schematics

DEFINITION: The auxiliary blower motor operates in at least one speed, but does not operate at the desired speed in one or more auxiliary blower motor switch 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 front blower motor switch in the maximum speed position.
3. Place the front mode switch in the vent position.
4. Place the auxiliary blower motor switch in each speed position.

Does the auxiliary blower motor operate at the desired speed in each speed position?

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

Go to Step 3

1. Turn OFF the ignition.
2. Disconnect the auxiliary blower motor resistor assembly.
3. Connect a test lamp between battery voltage and each control circuit.
4. Place the auxiliary blower control in the appropriate speed position for the circuit being tested.

Does the test lamp illuminate for each speed position selected?

Go to Step 5

Go to Step 4

Test the applicable auxiliary blower motor control circuit 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 9

Go to Step 6

Inspect for poor connections at the harness connector of the auxiliary blower motor resistor. 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 9

Go to Step 7

Inspect for poor connections at the harness connector of the 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 9

Go to Step 8

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

Did you complete the replacement?

Go to Step 9

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

Did you complete the replacement?

Go to Step 9

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2