The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the light are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level. For more detailed information concerning interior lamp operation refer to Interior Lighting Systems Description and Operation .

Battery voltage must be between 9-16 volts.

DTC B2652 00 will set for the following conditions:

The BCM will not DIM or illuminate any I/P lamps supplied by the I/P lamps dimmer switch signal circuit.

Schematic Reference

Interior Lights Dimming Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, observe the scan tool Dimming Control Reference voltage as the dimmer switch is activated from LOW to HIGH intensity. The reading should change as the switch is activated.

⇒	If the reading does not change as the switch is activated, refer to I/P Dimming Voltage Reference Malfunction.

⇒	If the reading changes as the switch is activated, refer to I/P Lamps Dimmer Switch Signal Malfunction.

I/P Dimming Voltage Reference Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10.

⇒	If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, test for B+ between the I/P dimming voltage reference circuit terminal 5 and ground.

⇒	If less than the specified range, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒	If greater than the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the I/P dimmer switch.

I/P Lamps Dimmer Switch Signal Malfunction

1. Ignition OFF, disconnect the C2 harness connector at the BCM.
2. Verify that a test lamp illuminates between the BCM 7 fuse voltage supply circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance.

3. Reconnect the C2 harness connector at the BCM.
4. Ignition ON, with a scan tool clear all DTCs.
5. Ignition OFF, disconnect the harness connectors at the following components:

•	Hazard switch

•	Power window switch - LR

•	Power window switch - RR

•	PRNDL lamp

•	Front sunroof switch

•	Rear HVAC switch - front

•	Rear HVAC switch - rear

•	Rear sunroof sunshade switch

•	Rear wiper switch

•	Steering wheel controls

•	Tow/haul switch

•	Traction control switch

6. Ignition ON, operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.

⇒	If the DTC resets, test the I/P lamps dimmer switch signal circuit for a short to ground. If the circuits test normal, replace the BCM.

7. Reconnect each component one at a time and verify that the DTC does not reset as current.

⇒	If the DTC resets as current, test or replace the component responsible for setting the DTC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.