B2420

CIRCUIT DESCRIPTION
The twilight delay pot sensor is a potentiometer. The instrument panel integration module (IPM) determines the control setting based on the voltage from the twilight delay pot sensor. As the resistance of the twilight delay switch varies, the voltage input to the IPM changes. The IPM performs a diagnostic test on the twilight delay input circuit every 150 milliseconds.

CONDITIONS FOR RUNNING THE DTC
^ The ignition switch is in the ON position.
^ The IP dimmer switch is set to MAXIMUM.
^ The headlamps are ON.

CONDITIONS FOR SETTING THE DTC
The IPM will set the DTC B2420 when it detects that twilight delay input is less than 5 Counts or greater than 250 counts for 3 consecutive tests.

ACTION TAKEN WHEN THE DTC SETS
The IPM will assume that the twilight switch is on and the twilight delay indicates the maximum.

CONDITIONS FOR CLEARING THE DTC
The IPM sees that the twilight delay input is between 5 and 250 Counts.

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.