So I have a amp and sub in my truck, the other day the sub would come on and off. So we were trying to fix it and find the problem so when we called it a night I put the head unit back in and it shut off and wouldn't turn on, so I thought it might of been the head unit cause it's somewhat old so I got a new one wired up and put in and nothin, so I was wondering is there a wire that could've got unhooked deep down in the wiring ??

 

so the new radio won't come on or just the amp?

Did you check radio fuses? There's a good chance when pulling or re-installing the radio that you pinched a wire and popped a fuse.

 

X2 on checking fuses, then test for power with the key turned. If the head unit isn't getting a signal it won't send a signal via the remote wire to turn the amp on.

 

The radio won't (head unit). I'm pretty sure I looked at the right fuse, it said radio and power mirrors, my mirrors worked fine and fuse looked fine

 

Get a test light and check for key off memory power usually the yellow and then check for key on power usually red. Also most aftermarket radios have a fuse of their own either in-line with the wires or on the back of the head unit Check that fuse too.

 

There is also one in the engine bay fuse box FYI, be sure to check both, also just because it looks good doesn't make it so, you can swap with a known working fuse of same amps. If you can pull all the fuses just in case who ever installed the stereo tapped into another circuit.

 

The fuse is good in the cab, it's the same fuse for power mirrors, and they work. And the head unit I got doesn't have a fuse on the back. And with the test light how do I check ??

 

put the clip of the light onto a good ground then poke the wire with the point end of the test light. If it likes you have power if it does not then you need to figure out why there is no power.

 

Ok, and my mistake it was the radio clock fuse I was looking at. Found the actual radio fuse and it's good, put a good one in just to make sure, and it was fine. So I'll try the test light

 

Alright I tested both red and yellow wire. Their getting power. Which leads me to??