B2643

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematics:

CIRCUIT DESCRIPTION
The twilight rheostate sensor is a potentiometer. The climate control panel (CCP) determines the control setting based on the voltage from the twilight rheostate sensor. The CCP controls the headlamps automatic on/off, delayed off functions.

CONDITIONS FOR RUNNING THE DTC
Enable flag is set to enable.
The CCP is powered.

CONDITIONS FOR SETTING THE DTC
The twilight rheostate voltage is greater than 4.8V.
The above condition is present for greater than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
Twilight status set to "ON".

CONDITIONS FOR CLEARING THE MIL/DTC
The CCP does not detect a voltage above the predetermined value during the diagnostic self test.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
5. Tests for a short to ground in the 5 volt reference circuit.