SCHEMATIC REFERENCES: HVAC Blower Control Schematics .

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

1. Turn ON the ignition, with the engine OFF.
2. Place the HVAC control in the VENT position.
3. Place the blower motor switch in each position (1, 2, 3 and 4).

Does the blower motor operate in all speeds?

Go to Symptoms - HVAC Systems - Manual

Go to Step 3

Does the blower operate in one speed only?

Go to Step 4

Go to Symptoms - HVAC Systems - Manual

1. Disconnect the blower motor resistor block.
2. Probe the suspect blower speed circuit with a test lamp connected to B+.
3. Turn ON the ignition, with the engine OFF.
4. Place the HVAC control in the VENT position.
5. Place the blower switch in the suspect position (1, 2, 3, or 4).

Does the test lamp illuminate?

Go to Step 6

Go to Step 5

Test the suspect speed circuit for an open/high resistance.

Did you find and correct the condition?

Go to Step 10

Go to Step 7

Inspect for poor connections at the blower motor resister block.

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 HVAC control head.

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 blower motor resister block. Refer to Blower Motor Resistor Replacement

Did you complete the replacement?

Go to Step 10

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Replace the HVAC control head. Refer to HVAC Module Assembly Replacement

Did you complete the replacement?

Go to Step 10

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Operate the vehicle in order to verify the repair.

Is the repair complete?

System OK

Go to Step 2