I purchased a 2003 blazer extreme last week it had the factory radio replaced with a Kenwood stereo with Cd player. I can slide the interior dimmer switch all the way up and the dome and dash lights will come on but in normal position i have no dash lights. I don't think it can be the fuse since they come on when i turn the dome lights on. Someone told me it may have to do with the wiring and the aftermarket stereo. I just don't know what wires they used when the hooked up the stereo. I pulled the switch out Saturday and everything looks clean. Any suggestions? I have already ordered a new switch.

 

While it's not completely impossible that the switch is bad, I would tend to lean toward the previous owner and how the HU was installed in this instance.

I've seen and repaired SO MANY issues from people cutting the factory harness plug and "testing" wires to find the right ones to hook up an aftermarket unit it's not even funny. Chances are they've hooked something up wrong behind the HU to the illumination wire. The factory harness has that connection so that the factory unit would dim with the dash. Very few aftermarket units with illumination inputs really do much with the dimmer, it's not necessary to even be hooked up.

Try your new switch, since you already ordered it, and see what you get. If it doesn't work you should pull the Kenwood and see what the wiring looks like in the back. If the plug and wires from the stereo don't go to another plug that plugs into the factory harness then they've likely cut it off and used whatever wires they thought made it work. Let us know what you find and if necessary we can help you further.

 

i might be a little late but mine does the same thing and i just have to balance the dimmer between on and the dimming part. (if that makes sense)