Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Did you perform the Lighting System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

1. Install the scan tool.
2. Cover the ambient light sensor.
3. Proceed to BCM inputs.
4. Select Twilight Sensor Voltage.

The status is determined by the input of the TS Day/Night circuit of the BCM connector C1. If the input is approximately 4.5, the status should be daytime. If the input is approximately 0 V, the status should be night time.

Does the scan tool display approximately 0 volts?

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Go to Step 3

Go to Step 4

1. Disconnect the BCM connector C1.
2. Turn the twilight sentinel switch to the ON position.
3. Use a DMM in order to measure the resistance between the TS On/Off circuit of the BCM connector C1 and a good ground.

Is the measured resistance equal to the specified value?

Less than 2 ohms

Go to Step 13

Go to Step 8

1. Disconnect the headlamp automatic control ambient light sensor connector.
2. Use a DMM in order to measure the voltage between the + 5 volt reference circuit of the headlamp automatic control ambient light sensor connector and a good ground.

Is the measured voltage equal to the specified value?

+5 V

Go to Step 5

Go to Step 9

Test for an open or high resistance or short to ground or short to voltage in the TS Day/Night circuit of the headlamp automatic control ambient light sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 14

Go to Step 6

1. Disconnect the headlamp automatic control ambient light sensor connector.
2. With the scan tool observe the Twilight Sensor Voltage.
3. The status is determined by the input of the TS Day/Night circuit of the BCM connector C1. If the input is approximately 4.5, the status should be daytime. If the input is approximately 0 V, the status should be night time.

Is the measured voltage equal to the specified value?

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Go to Step 12

Go to Step 7

Test for a short to B+ in the TS Day/Night circuit of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 14

Go to Step 11

Test for an open or high resistance in the TS On/Off circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 14

Go to Step 10

Test for an open, high resistance, short to ground or short to voltage in the + 5 volt reference circuit of the headlamp automatic control ambient light sensor connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 14

Go to Step 11

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the repair?

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Go to Step 14

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Replace the heater and the A/C control. Refer to HVAC Control Module Replacement in Instrument Panel, Gauges and Console.

Did you complete the repair?

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Go to Step 14

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Replace the headlight automatic control light sensor. Refer to HVAC Control Module Replacement in HVAC Systems.

Did you complete the repair?

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Go to Step 14

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Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

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Go to Step 14

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1. Connect all connectors and components that were previously disconnected.
2. Verify that the twilight sentinel system operates properly.

Does the twilight sentinel system operate properly?

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System OK

Go to Step 2