B2556

Diagnostic Chart:

Schematics:

CIRCUIT DESCRIPTION
The interior lamp dimmer switch is a potentiometer. The instrument panel module (IPM) determines the control setting based on the voltage from the interior lamp dimmer switch. The IPM sends out a class 2 message to the dash integration module.

CONDITIONS FOR RUNNING THE DTC
The IPM is powered.

CONDITIONS FOR SETTING THE DTC
The interior lamp potentiometer voltage is less than 0.09 V or greater than 4.75 V.

ACTION TAKEN WHEN THE DTC SETS
The IPM sets the dimming level to full brightness for all displays.

CONDITIONS FOR CLEARING THE DTC
The IPM does not detect a voltage that is less than or greater than the predetermined value during the diagnostic self test.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
3. This step tests for 5 volt reference voltage at the fog lamp switch.
4. This step tests the signal return circuit for an open or short to power.
5. This step test the IP Dimmer input circuit for an open or short to ground.