FixVault

Interior Backlighting Does Not Dim

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
Interior Backlighting Does Not Dim

Step Action Yes No
Schematic Reference: Interior Lights Dimming Schematics 
Connector End View Reference: Master Electrical Component List in Wiring Systems
1 Did you perform the Lighting Systems Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Lighting Systems 
2 Verify that the interior backlighting does not dim.
Does the interior backlighting operate normally?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3 Do the I/P lamps dim? Go to Step 13  Go to Step 4 
4 Do the class 2 lamps dim? Go to Step 5  Go to Step 6 
5 Test for a short to battery positive voltage in the instrument panel lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 14  Go to Step 13 
6 Disconnect the I/P dimming switch.
Does all the illumination of the backlight components turn OFF?
Go to Step 8  Go to Step 7 
7 Test for a short to voltage on the I/P dimming control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 14  Go to Step 8 
8 Test for a poor connection, open or a short to ground in the I/P dimming control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 14  Go to Step 9 
9 Test for a poor connection or an open in the I/P dimming return circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 14  Go to Step 10 
10
  1. Reconnect the interior lamp switch.
  2. Disconnect the BCM connector C1.
  3. Using a DMM, measure the resistance between the I/P dimming voltage reference circuit and the I/P dimming control circuit.
  4. Vary the I/P dimming switch from full bright to full dim.
Does the DMM, display change?
Go to Step 13  Go to Step 11 
11 Test for an open or a short to battery positive voltage in the I/P dimming voltage reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 14  Go to Step 12 
12 Replace the I/P dimming switch. Refer to Instrument Panel (I/P) Dimmer Switch Replacement .
Did you complete the replacement?
Go to Step 14  -
13
IMPORTANT: Perform the setup procedures for the body control module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.
Replace the body control module (BCM). Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?
Go to Step 14  -
14 Operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 2