Dimming Level Switch Input Circuit High

DIMMING LEVEL SWITCH INPUT CIRCUIT HIGH

WHEN MONITORED
Ignition on.

SET CONDITION
BCM detects a voltage greater than 4.75 volts on the dimming level switch input for more than 5 seconds.

POSSIBLE CAUSES
- Panel lamps dimmer switch mux open
- Short to battery
- Multifunction switch
- Body control module

DIAGNOSTIC TEST

1. INTERMITTENT CONDITION
Turn the ignition on.
With the scan tool, clear all BCM DTC's.
Actuate the Dimming Level Switch.
With the scan tool, read the DTC information.

Q: Does the scan tool read: Dimming Level Switch Input CKT High?

YES: Go To 2
NO: The condition is not present at this time. Monitor scan tool parameters while wiggling the related wire harness. Refer to any Technical Service Bulletins that may apply. Visually inspect the related wiring harness and connector terminals.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. PANEL LAMPS DIMMER SWITCH MUX OPEN

Turn the ignition off.
Disconnect the BCM C2 harness connector.
Turn the ignition on to check the Courtesy Lamp operation.

Q: Did the Courtesy Lamps come on?

YES: Go To 3
NO: Repair the Panel Lamps Dimmer Switch MUX circuit for an open condition.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

3. SHORT TO BATTERY
Ensure the Junction Block C24 harness connector on the front of the junction block is connected.
Turn on all overhead, map and rear rearing lamps by their own individual switches.
This will disconnect each lamp from the Courtesy Lamp Driver Circuit.

Q: Did any lamp fail to light when it was turned on by it's own switch?

YES: Repair the short to battery condition.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 4

4. MULTIFUNCTION SWITCH
Turn the ignition off.
Disconnect the Junction Block C24 harness connector from the front of the junction block.
Remove the Body Control Module from the junction block.
Measure the voltage of the Courtesy Lamps Driver circuit.

Q:Is there any voltage on the Courtesy Lamps Driver Circuit?

YES: Replace the Multifunction Switch.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test