B2642

CIRCUIT DESCRIPTION
The twilight delay switch is a potentiometer. The HVAC control module determines the control setting based on the voltage from the twilight delay switch. The HVAC control module controls the headlamps automatic on/off and delayed off functions.

CONDITIONS FOR RUNNING THE DTC
^ Enable flag is set to enable.
^ The HVAC control module is powered.

CONDITIONS FOR SETTING THE DTC
^ The twilight delay switch voltage is less than 0.2 V.
^ 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 DTC
The HVAC control module does not detect a voltage below the predetermined value during the diagnostic self test.

TEST DESCRIPTION

Steps 1-4:

Steps 5-15:

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.