Interior Backlighting Does Not Dim

WARNING: This page is about a different car, the 2004 Buick Regal and 2004 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

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 System Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Lighting Systems
2	Turn the ignition to the ON position. Turn the headlamp switch to the OFF position. Turn the headlamp switch to the PARK position. Do the vacuum florescent lamps dim when the park lamps are turned on?	Go to Step 3	Go to Step 4
3	Turn the I/P lamp dimmer switch to the low position. Do the I/P lamps dim?	Go to Testing for Intermittent Conditions and Poor Connections in Writing Systems	Go to Step 5
4	Test for a open or high resistance in the instrument panel lamps fused supply voltage - 1 circuit of the non dimming vacuum florescent component. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 8	Go to Step 7
5	Test for a short to battery positive voltage in the instrument panel dimmer switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 8	Go to Step 6
6	Replace the headlamp switch. Refer to Headlamp Switch Replacement in Instrument Panel, Gages, and Console. Did you complete the repair?	Go to Step 8	-
7	Replace the inoperative component. Did you complete the repair?	Go to Step 8	-
8	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2