Schematic Reference: HVAC Schematics

DEFINITION: The auxiliary blower motor switches do not operate in each speed position.

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

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 auxiliary blower motor switch in each speed position.
3. Place the front auxiliary blower motor switch in the rear position.
4. Place the rear auxiliary blower motor switch in each speed position.

Does the auxiliary blower motor work properly 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.
3. Turn ON the ignition, with the engine OFF.
4. With a test lamp that is connected to battery positive voltage probe each auxiliary blower motor control circuit and place the appropriate control switch in the appropriate position for the control circuit being tested.

Does the test lamp illuminate for each control circuit?

Go to Step 8

Go to Step 4

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

Did you find and correct the condition?

Go to Step 12

Go to Step 5

Is the condition present from the front auxiliary control?

Go to Step 6

Go to Step 7

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 12

Go to Step 10

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 12

Go to Step 11

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 12

Go to Step 9

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

Did you complete the replacement?

Go to Step 12

--

Replace the front auxiliary HVAC control assembly. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

Go to Step 12

--

Replace the rear auxiliary HVAC control assembly. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

Go to Step 12

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2