B2622

DTC B2622

DTC DESCRIPTOR

DTC B2622
Display Dimming Pulse Width Modulation (PWM) Input Circuit Low




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure Initial Inspection and Diagnostic Overview.

CIRCUIT/SYSTEM VERIFICATION
Ignition ON, observe the scan tool I/P dimmer input. The reading should be between 0.0 and 4.5 volts and change with the operation of the dimmer switch.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the harness connector at the dimmer switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit and ground.
- If greater than 1.0 ohm, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
3. Ignition ON, verify the scan tool I/P dimmer input is greater than 4.5 volts.
- If less than 4.5 volts, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3-amp fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool I/P dimmer input is less than .5 volts.
- If greater than .5 volts, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, test or replace the dimmer switch.

COMPONENT TESTING
1. Ignition OFF, disconnect the harness connector at the dimmer switch.
2. Test for 20 ohms to 10.0Kohms of resistance between the signal terminal and the ground terminal.
- If the resistance is not within the specified range, replace the dimmer switch.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure Verification Tests.

Instrument Panel Dimmer Switch Replacement