Head unit wont come on

[ShagggDiesel 25]

I sold my old HU to a buddy the other day, so I went to wal mart for a quick fix and bought a 100$ JVC something-or-other to replace it. I wired the ground, the 12v, and the ignition, and nothing happens when I turn the key. I didn't wire any of the speakers, for I am just running RCA's to an external amp to power my mids and highs. I've checked all fuses, including the one in the HU itself, and re-wired everything just to be sure. After that didn't work, I took it back to wal-mart to replace it, and when I wired the new one up, still nothing, so I know it's not a problem with the HU itself.. Any ideas on what could be the problem?

[CrazyKenKid 64]

well it isn't coming on so that means there isn't any power going to it OR the ignision wire is jacked.

try to trace the ignision wire (yellow one i think) and look for cuts or breaks and repair with black tape. also to see if the hu work simple hook up the ground, then twist the ign and 12volt + together and touch those to a power source (battery) and see what happens if it turns on you are good to go if it does...sol.... also keep in mind when you twist those wires together i don't know if that is the best way to do it but let someone else chime in and tell me i am wrong just to be certain...

also be sure to check both your 12v and ign wire and it wouldn't hurt to check them with a dmm either, do a continuity test with a buddy!

[CrazyKenKid 64]

although from memeory bakc in the day when i wired in my JVC h/u i got the ign and 12volt wires crosssed and my h/u didn't work plus my harness was a pile....so basically i ended up switching my ign and 12volt wires and bam it worked!!

also be sure to ground to the chassis of the car and not the harnes!!

[ShagggDiesel 25]

What's the problem with wiring the ground to the harness? My last HU was wired to the harness and it grounded and worked fine. Also, the 12v and ignition are color matched. Red - Ignition, Yellow - Constant 12v. I'll try crossing them but I don't think thats an issue. And since my ground to the harness worked with my last HU, I assume it would work with another?

[cheese20323 13]

]Well if the old HU you had was the same brand of the new one it should fit. But if it doesn't you will have to do every thing all over with the harness that came with the HU.

[ShagggDiesel 25]

I know that.. I re did the wiring on the harness to the wiring on the HU.

[jcarter1885 995]

I have had this problem some way one of your power wires on your wiring harness are shot, so you will need to wire both your red and yellow wire from headunit to either the read wire or yellow wire on wiring harness to see which one works. More than likely the Ignition wire is shot so it wont come on with the ignition, if that is the case you can just run a wire to fuse panel inside the car and find the fuse for turn-on/ignition (wrap that wire around one of the prongs on the fuse and plug it in. Thats how I did mine and has been fine for over year, I threw a perfectly good radio away thinking it was the radio and was an issue with my factory wiring. Hope its not that serious but if any more question just ask.

[ShagggDiesel 25]

OK so I wired the ignition, and the 12V all together and the unit comes on and works fine with the key is turned on. Only problem, when I turn the key off, it resets the whole unit, so I have to adjust EQ and settings everytime I turn the car on. This is the only way I've been able to get the unit to work though. I DID however try switching the 12v and ignition wires (red to yellow and yellow to red) from the harness to the unit, and it would come on for about 3 seconds and turn off and not turn back on.. but if you pressed "source" the clock would come on for a few seconds, but thats it. There is nothing wrong with the ignition lead or anything from what I can see, and other hesd units work fine. Any ideas on what to do?

[PhishHead 6]

Did you ever check to see if maybe you blew a fuse when putting the new head unit in? And dont just check the one that says stereo. I made that mistake once and it was some other fuse. Didnt know if you had checked that yet or not.

[ShagggDiesel 25]

Did you ever check to see if maybe you blew a fuse when putting the new head unit in? And dont just check the one that says stereo. I made that mistake once and it was some other fuse. Didnt know if you had checked that yet or not.

I think I've checked every fuse that is in my car. LOL

[DrgUpsy 0]

Get you a test light and check the wires.....That's a given. find out if it's the 12volt or switch....Hell could even be your ground check it to.

[CrazyKenKid 64]

go with what jay-cee suggested but before you go do what DrgUpsy said with the test light (they are cheap at radioshake and good to have around) and it does hurt to try a differnt ground spot,

maybe when you pulled the old h/u out something happended like old wiring gave out...or fused popped, to chekc a fuse you need a dmm and touch the top and bottom of the fuse and make sure you get the same voltage on top and on the bottom of the fuse, and ground your dmm (black wire) to a piece of steel on the car.

and if all else fails... give what jay-cee said a shot!