1. Turn on the ignition leaving the engine off.
2. Turn off the blower speed control.
3. Disconnect the blower motor connector.
4. Use the J 39200 DMM and measure the voltage at terminal C of the blower control input.

Does the voltage measure near the specified value?

5 V

Go to Step 5

Go to Step 2

1. Disconnect the HVAC programmer blower control output from the blower control module at pin C.

Leave the battery and ground connected to the blower control module.

2. Measure the voltage at pin C of the blower control module.

Does the voltage measure near the specified value?

5 V

Go to Step 3

Go to Step 6

Inspect the HVAC programmer blower control output circuit for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

System OK

Go to Step 4

Replace the HVAC control assembly. Refer to Control Assembly Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the repair?

--

System OK

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1. Disconnect the blower control input connector.
2. Measure the resistance from terminal A to terminal B of the blower control input connector.

Does the resistance measure less than the specified value?

20 ohms

Go to Step 6

Go to Step 7

Replace the blower control module. Refer to Blower Motor Control Module Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the repair?

--

System OK

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

Did you complete the repair?

--

System OK

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