i got a pioneer deck. the problem is that it turns on and off. i checked my harness connections but everything seems fine. anybody knows what it is or had this happen to them before? should i get a new harness or is it the deck? my brother thought that it might be the harness but isn't sure.

check if your head unit has a ground to. Mine didnt work for the longes and i found out that you have to ground the actuall head unit... maybe yours is lose or a ground is lose.. a harness cant really go bad unless you pull the wires out or it some form of liquid got on it..

i would say it's a bad ground somewhere

should i run a seperate ground from the head unit to chassis? and if yes where would be a good spot and what size wire should i use to ground?

should i run a seperate ground from the head unit to chassis? and if yes where would be a good spot and what size wire should i use to ground?
You can use any metal structural part that is fastened to the chassis to ground it.
I'd suggest you go with the same gauge wire but it does'nt really matter.

-Eric

My deck has just started to do the same thing, one thing I noticed is that it only does it when the car is idle. As soon as I'm going down the road the head unit comes on...could this have something to do with a bad alternator ground? I've noticed that my lights are dimmer lately at idle, and as soon as I'm accelerating my lights brighten up and my head unit turns back on. Any help would be great.

i don't think it's the alternator. i think it's the ground like they said. my now is just dead. gonna rewire the ground but waiting till it's warmer outside.

that happened to me and it was the alternator

bad ground or a wire is split and is touching another bare wire or metal back there

replace fuse for the deck as well

as far as ur idle=redo ur battery connections...or strip the power and ground cable a bit and buy new terminals

My Pioneer deck was doing this not to long ago, I regrounded it and it would still cut on and off. What I did to fix mine was run a direct power wire to the deck 12V battery wire (not acc wire) straight from the battery instead of the harness. Works fine now.