Help ! Another Dashboard Light Problem .......

Well after getting a new battery/alternator I have had a number of electrical problems on my 2007 Aveo LT. Now down to last one - that i know of. Dashboard, center console lites not working. All fuses are good. Today I pulled the dimmer switch. Ground is good there. I checked the voltage on both the brn/wht wires. Both of them were 4.5 volts. I assume of one them should be in the 13 volt range. I assume power leaves the dimmer and goes to the console lites. My question is: does anyone know where the power comes from that goes to the dimmer. I will work my way backward as I assume there a wiring problem with that wire. I cant find a diagram, not sure I could read it anyway. There is no splicer in the underhood fuse box in my car.

Thank you. Any help/ideas would be appreciated.

Here is a pic of the dimmer control. The dimmer works on limiting the flow from ground (yes electricity flows from ground to positive). So at full on the dimmer should have +11 VDC on the brn/wht wires measured to ground.
Attachment 10242

Xinter thank you for posting the above. I will print it out and study it, then try the dimmer again to ensure i dont have 11dcv while the dimmer at its brightest. If I dont, i assume i am not getting proper voltage to the switch, therefore a problem upstream. One thing (of many) I dont understand, the radio lites are working. The dimmer has no effect on them. Any comments, tips, suggestions are more than welcome. Thank u.

This fixed my problem!!!!

SIDE JOB: Chevy Aveo lights not working « Acura Integra Tips and DIY

******************** Update FIXED *************************

Over 3 months I spent 20-30 hours working on this and had 3 auto repair shops try to fix. No one could find where power was dropping to the dimmer switch (never got more than 4 volts to the dimmer). My car did not have the underhood splice pack that is mentioned often on these boards. I never had confidence in the diagrams I was able to find, often they just didnt match. Anyway, finally said screw it. I ran a wire from the underhood fuse box (tied in to the RH/PK fuse) direct to the input of the dimmer. Worked. Lites On !!!! Glory Glory. Lesson learned. Thanks to all for your help.