Schematic Reference: HVAC Schematics

DEFINITION: The blower motor is inoperative in all speed positions.

1

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

Important: The mode switch must remain in any position except OFF throughout this diagnostic procedure.

1. Turn ON the ignition, with the engine OFF.
2. Place the mode switch in any position except OFF.
3. Place the blower motor switch in each speed position.

Does the blower motor operate in any speed position?

Go to Blower Motor Malfunction

Go to Step 3

1. Turn OFF the ignition.
2. Disconnect the blower motor.
3. Turn ON the ignition, with the engine OFF.
4. Probe the blower motor supply voltage circuit of the blower motor with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 7

Connect a test lamp between the blower motor supply voltage circuit and the high blower motor control circuit of the blower motor.

Does the test lamp illuminate?

Go to Step 14

Go to Step 5

Test the high blower motor control circuit for an open or high resistance between the blower motor and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 6

Test the blower motor switch ground circuit of the HVAC control assembly 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 21

Go to Step 15

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

Did you find and correct the condition?

Go to Step 21

Go to Step 8

1. Turn OFF the ignition.
2. Disconnect the blower motor relay.
3. Turn ON the ignition, with the engine OFF.
4. Probe the battery positive voltage circuit of the blower motor relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 16

9

Probe the blower motor relay supply voltage circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 11

Test the ground circuit of the blower motor relay 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 21

Go to Step 13

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

Did you find and correct the condition?

Go to Step 21

Go to Step 12

1. Turn OFF the ignition.
2. Disconnect the HVAC control assembly.
3. Turn ON the ignition, with the engine OFF.
4. Probe the ignition 3 voltage circuit (mode switch supply voltage circuit) of the HVAC control assembly with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 15

Go to Step 17

Inspect for poor connections at the blower motor relay. 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 21

Go to Step 18

Inspect for poor connections at the blower motor. 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 21

Go to Step 19

Inspect for poor connections at the 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 21

Go to Step 20

Repair the battery positive voltage circuit of the blower motor relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 21

--

Repair the ignition 3 voltage circuit of the HVAC control assembly. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 21

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

Did you complete the replacement?

Go to Step 21

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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 21

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

Did you complete the replacement?

Go to Step 21

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2