I have the stock system in my car and I usually have the bass turned all the way up, when the bass hits the dome light dims a little bit. I'm not too concerned, I have the stock battery in the car still. If I were you and didn't want this to happen I might put a bigger capacitor in your system.

 

I don't even have subs installed. I'm just wired for them.

 

this may sound random. but do you have an amp wired in right now? if so what kind? mono-block(aka class D) or 2-channel, 4-channel? if your wired for a sub its probly a mono. and what could be happening is the draw from the amp is whats making the lights dim all thetime or the stereo shut off. because its drawing on what charges the cars battery(aka the alternator)

ive seen it before like mopar kyle says put a bigger capacitor in. or if there is an amp. take it out and see. the dimmming of the lights may make it seem like an alternator but could be an amp... also if you do have an amp. what brand/wattage is it. i work at a future shop in canada in the car audio section so i know a lil bit about car stereos. ha ha

also on a side note
the more the bass pounds.. the more the lights will dim which is why they make capacitors :P

 

I don't know what brand the amp is. Just a knockoff brand that a friend sold me. I have a cap, just too lazy, dont care enough to install it. haha

 

ha ha i see. i have the same motivation level as you. but chances are the cause off your stereo turning off is due to, the amp.... also just thought of this now... but when you wired for the amp did you ground the amp and reground the stereo when you took it out? could also be the cause......

 

The stereo isnt grounded to anything, but I've had my stereo for a couple years now problem.

 

hmmm could be the problem now that its wired for a sub... if you pull the stereo and look atthe wires coming from the back of the factory, to the wiring harness the black wire off the unit is the ground(like most cases) if its not connected to another black wire on the wiring harness its not grounded at all. if it is connected to another black wire on the wiring harness it is ground, and that could be causing an issue....

 

Its not JUST the stereo turning off. The lights dim and such. When I roll my power windows down at the same time, my lights dim then.

 

Power windows make lights dim in every car. They use a lot of power.

 

They never used to..in mine.