Is it possible to add a capacitor to a car's electrical system even if you don't have an aftermarket stereo or amp? Reason I ask is cause my truck the lights dim a little bit when I flip on the off road lights and I was wondering if adding a cap in line on the main power line to the lights would prevent this? Would it hurt anything like my alternator?

 

No it wont hurt ur alt try to do the big 3 that will help u

 

check the voltage your battery sits at with the car off and minimal accessories on (cant really prevent the trunk light) It might be time to replace the battery. Otherwise, yes you can add a cap without having a aftermarket radio system BUT i would make sure there's nothing wrong as far as battery or alt first Then big 3 as necessary (it doesn't really make a huge impact in the cobalt. The battery terminal and ground are really 90% or more of what you can get with the wiring without having any non stock accessories) and a cap last