1. Disconnect the ambient outside temperature sensor harness connector.
2. Turn the ignition switch to the RUN position.
3. Place the heater-A/C control in the AUTO position.
4. Use a digital multimeter (DMM) in order to measure the voltage between the ambient outside air temperature sensor harness connector terminal  A (circuit 735) and ground.

Is the measured voltage within the specified range?

4-6 V

Go to Step 2

Go to Step 3

Replace the ambient outside temperature sensor. Refer to Ambient Temperature Sensor Replacement .

Is the repair complete?

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Go to Step 8

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1. Place the ignition switch in the OFF position.
2. Disconnect the ambient outside air temperature sensor harness at connector C 120.
3. Use a test lamp, connected to B+, in order to probe the ambient outside air temperature sensor harness at connector C 120 terminal B.

Does the test lamp light?

--

Go to Step 4

Go to Step 5

Locate and repair a short to ground in circuit 735 (LT GRN/BLK) between connector C 120 and the ambient outside air temperature sensor.

Is the repair complete?

--

Go to Step 8

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1. Disconnect the heater-A/C control module assembly.
2. Use a test lamp, connected to B+, in order to backprobe the heater-A/C control harness connector terminal D 3.

Does the test lamp light?

--

Go to Step 6

Go to Step 7

Locate and repair a short to ground in circuit 735 (LT GRN/BLK) between the heater-A/C control module assembly and connector 120.

Is the repair complete?

--

Go to Step 8

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Replace the heater-A/C control. Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Step 8

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Verify that the system operates properly.

Does the system operate properly?

--

System OK

Go to Diagnostic System Check