Here's some info from the service 
CD: (need to check 9 fuses!)
The instrument panel dimmer switch sends a signal to the 
instrument cluster which then sends a backlighting intensity and dimming curve command over the standard corporate protocol (SCP) link to the 
front electronic module (
FEM), the audio unit, and the dual automatic temperature control (
DATC) module. The 
FEM then sends a pulse width modulated (PWM) dimming signal to the 
instrument cluster, the dimmable LEDs, and the dimmable incandescents. 
Fault Management 
The dimmable backlighting will default to 100% intensity if an instrument panel dimmer switch failure occurs. 
Inspection and Verification 
Binding or damaged instrument panel dimmer switch 
Central junction box (CJB) fuse(s) 
13 (5A) 
20 (10A) 
30 (5A) 
33 (10A) 
Rear battery junction box (BJB) fuse(s) 
10 (30A) 
14 (30A) 
23 (5A) 
31 (30A) 
41 (15A) 
 
------------------
Ron
VIN #7729, seq.#7505, blue premium,
partial blue interior, no top, Louisville Ky.