1. Disconnect the blower motor resistor connector.
2. Turn the ignition switch to the ON position.
3. Place the heater-A/C control in the VENT position.
4. Place the blower switch in the inoperative position.
5. Use a test lamp to backprobe between ground and the blower motor resistor connector terminal listed below:

•	LO: Terminal B.

•	M1: Terminal A.

•	M2: Terminal D.

•	M3: Terminal C.

Does the test lamp light ?

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Go to Step 2

Go to Step 3

Replace the blower motor resistor. Refer to Blower Motor Resistor Replacement in HVAC Systems .

Is the repair complete?

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System OK

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1. Turn the ignition switch to the OFF position.
2. Disconnect the heater-A/C control connector C 1.
3. Check for a poor connection, an open, or a short to ground in the inoperative circuit listed below:

•	LO: Terminal B.

•	M1: Terminal A.

•	M2: Terminal D.

•	M3: Terminal C.

Is there a poor connection or an open in the inoperative circuit tested?

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Go to Step 4

Go to Step 5

Repair the fault in the circuit.

Is the repair complete?

--

System OK

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Replace the heater-A/C control. Refer to Control Assembly Replacement in HVAC Systems with A/C - Manual.

Is the repair complete?

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System OK

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