So I have a 2001 Monte Carlo LS , bought an aftermarket radio and tried installing it, cut the factory clip off and tried to run the factory wire to the radio harness, couldn't realizing the ignition needed spliced. Then I realized that the lights that come on in the car to see how fast I'm going etc. won't come anymore and my tail lights aren't coming on at night, anybody know if I blew a fuse and which if I did?

 

I'am having a similar problem: Instrument Panel lights not illuminating, including shift gear lighting, gotta go by feel when shifting out of Park and into Drive. I'am going to check fuses 1st, then the Rotary Switch **** that actually turns and adjust illumination inside the Instrument Panel (all gauges +).

 

Did you disconnect the battery before the install? If not, it could very well be a fuse specially if your tail lights are out too. Look at the first box or your owners manual for the correct fuses to check. I don't know them off the top of my head otherwise I'd help more but does sound like a fuse thing

 

One day my service vehicle soon light came on. Shortly after I noticed that all my interior lights were out. Thought it must be a fuse. Checked every fuse and found nothing. Shortly after this I was away for a month and my monte was left in the garage. Unknowingly I left my GPS plugged in and on. When I returned home the battery was dead. Put the charger on for the night and the next day it started. The check vehicle soon light was out. And the interior lights were all working again. I have no idea what one had to do with the other but the cvs light is still out and all the interior lights are working. Does that have anything to do with your issue? I have no idea. But something was wrong that seemed to somehow get fixed after I killed and charged the battery. I can't explain it but there you go for what it is worth.