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 auxiliary blower motor switch in each speed position.

Does the auxiliary blower motor operate correctly 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 for the auxiliary blower motor.
3. Turn ON the ignition.
4. Connect a test lamp between the ignition 3 voltage and the faulty blower motor control circuit.
5. Place the auxiliary blower motor switch in the faulty speed position for the circuit being tested.

Does the test lamp illuminate for the appropriate speed position selected?

Go to Step 6

Go to Step 4

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

Did you find and correct the condition?

Go to Step 10

Go to Step 5

Test the high blower motor control circuit at the auxiliary blower motor resistor assembly for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 7

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 10

Go to Step 8

Inspect for poor connections at the harness connector of the 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 10

Go to Step 9

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

Did you complete the replacement?

Go to Step 10

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

Did you complete the replacement?

Go to Step 10

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Operate the system in order to verify the repair.

Did you correct the condition?

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Go to Step 2