so my head unit stopped working ages ago, and i never got around to it. so today i pulled it all out. im getting power from my yellow battery wire, the blk gnd wire is good, and the red accessory wire is hooked up but not receiving power? i dont know it should be. ive also got the harness that plugs into the head unit. what wires require power for it to turn on? do the wires just need power to turn on or am i missing something? all the odd colors are for the speakers, i know that much. ive been using this diagram:

http://www.the12volt.com/request/request2.asp

but i cant get it to turn on, thanks in advance

 

Have you put a meter on those wires and actually checked for voltage to make sure you have it? And just to clarify, are you adding this HU in your truck or your car?

 

yup, checked em with the voltmeter, and in my 71 nova.

 

Ok, good. So whats the model number if the HU so we can find a wiring diagram and get you the right wires...........

 

have you checked the fuse on the HU

 

Nevermind, just read your response about the Nova....

 

Red should key key on voltage. I would check the fuse where it is hooked to the car (fuse panel?).

 

Just to make sure you have a good HU and didn't buy a bad one. pop your hood twist the yellow and red wires together put them on the positive to your battery and black to neg. if you have a good after market HU then it should have it's own fuse so you should be safe.
Also had similar problem with a 78 camero and it turns out that bubba was using the field flash wire for the alternator as main feed for the HU and the HU didn't like it.

 

umm you said it stopped werking ages ago, so maybe its broken