lights flicker w/ head unit

Whenever i turn on the head unit for my stereo, it flickers my lights. also, when i'm sitting without the engine running, my dome light will dim itself out once n' a while. i'm thinking ground issues....any thoughts?

thanks

^^ Agreed with that comment.

Pull the fuse for your sub amp and see if the HU by itself causes voltage fluctuations.  If so, pull it and inspect the wiring installation.  Plus, depending on how old it is, it IS a Pioneer, which is pretty much a disposable brand when they start having problems.

hmmm, maybe i'll swap out my deck. without the engine running, my dome light cuts it's light output in and out. if that makes sense. it will be bright, then dim a bit, then brighten itself up. that shouldn't have anything to do with my alternator should it?

thanks

Does the fluctuation follow the music (meaning when it is louder or when there is more bass, the light gets dimmer)?  If so, and the engine is off, then it's simply that the system is too much for your battery.  This is very common, and why I suggested pulling the sub amp fuse to see if it is related to your head unit (as you apparently think) or if it is a simple overload situation.   If it does not follow the music, then you have a bad wiring issue or a defective piece of gear.

No, this is when i'm just sitting in my truck with the radio low, not loud at all. the only issues that i see with my stereo, is when i turn my deck on, that's when the headlights will flicker. but if i'm just sitting in the truck listening to whatever, the light does it's dim, bright, dim......and so on.

thanks