Schematic Reference : HVAC Schematics

DEFINITION: The blower motor is inoperative in every speed position.

Did you review the 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 mode selector to the vent position.
3. Place the blower motor switch in each speed position.

Is the blower motor inoperative in each speed position?

Go to Step 3

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

3

1. Turn OFF the ignition.
2. Disconnect the blower motor.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the blower motor supply circuit and ground.
5. Place the blower motor switch in the minimum speed position.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

1. Connect a test lamp between the blower motor supply circuit and the blower motor ground circuit.
2. Place the blower motor switch in the minimum speed position.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

5

Important: The blower motor switch must be in the correct speed position for the control circuit being tested. Failure to do this will result in a misdiagnosis.

1. Turn OFF the ignition.
2. Disconnect the connector C1 at the blower motor resistor assembly .
3. Turn ON the ignition, with the engine OFF.
4. Place the blower motor switch in the minimum speed position.
5. Probe the control circuit of the low blower motor with a test lamp that is connected to ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 6

Test the ignition 3 voltage circuit of the HVAC module for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 7

Test each blower motor control circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 11

Test the ground circuit of the blower motor resistor assembly for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 10

Inspect for bad connections at the harness connector of the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 13

Inspect for bad connections at the harness connectors of the blower motor resistor assembly. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

Inspect for bad connections at the harness connectors of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 12

Replace the HVAC module. Refer to Heater and Air Conditioning Control Replacement .

Did you complete the replacement?

Go to Step 15

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Replace the blower motor. Refer to Blower Motor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

Go to Step 15

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

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 2