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daveyp225
06-19-2009, 11:11 AM
I just installed a Pioneer Preimer P680MP head unit into my 1995 Mustang GT. The care came with the stock Mach 460 with the factory amps.

I purchased the following harness: http://www.crutchfield.com/p_120705510/Ford-Receiver-Wiring-Harness.html?search=ford+harness

After splicing the required wiress to the aftermarket head unit adapter it wouldn't power up. I had connected both the red ACC switch power and yellow constant power wires. Nothing...

I put off putting wire nuts on, and the yellow and red spliced wires contacted, and the **** thing started to power up... Hmm, I thought to myself. I figured maybe either the red or yellow wire was not connected correctly. I tried yellow->red, red->yellow. Still didn't work...

So I spliced the red AND yellow wire from the head unit to the incomming yellow, and it works!

I felt like saying screw it, keep it that way... But I know somthing isn't right and it might cause me problems. What could be the issue here? My head unit is also getting very hot to the touch, and I can smell a bit of burning after its playing a CD for 5 minutes.

thaster
06-19-2009, 11:15 AM
you should never ever do trial and errors on wires! go find the wire diagram for your car and wired it accordingly such as rear speaker positive of harness to rear speaker positive of car.

cx-7heaven
06-19-2009, 11:17 AM
The burning smell will probably go away, it is because of the sealant they use on circuits. As far as your wiring goes, I had that problem as well on my Dodge. I just wired it up to coninuous battery and switch it off when I shut down. It more than likely is because the Mach460 uses multiple wires to turn on, which your pioneer is not compatible with. My friend's 07 Escape did the same thing, and I had to find a switched positive for his deck, couldnt use the wiring harness positive for it.

cx-7heaven
06-19-2009, 11:20 AM
you should never ever do trial and errors on wires! go find the wire diagram for your car and wired it accordingly such as rear speaker positive of harness to rear speaker positive of car.


His harness that he bought is compatible, and switching the yellow red is only switching switched for constant positive, hes ok with that

daveyp225
06-19-2009, 11:44 AM
Thanks for the helpful replies. I went out to check again and realized I made a mistake in my description. I have both the red and yellow power wires running from the head unit to the red/ACC from the harness.

I wasn't doing "trial and error" per se. It was an accidental connection. I knew both lines had the same voltage so I figured it was safe. This can be dangerous in general, I know.

I have come to 2 conclusions, which may be incorrect due to my limited knowledge.

1) Since the red incoming line has power, and my HU will still not power up with this only connected, both the Yellow and Red wires on the HU must be connected to power.

2) The "correct" wiring method did not work, but running both the red and yellow from the HU to the incomming red/ACC did work. I feel this implies the yellow/constant incomming power is not working. I cannot see any broken connections, so I'm leaning towards the harness being the problem.

If #2 above is correct, could I bipass the harness? If so, which color wire is the "constant power" in the factory harness? I notice Ford uses different colors for the other side of the adapter.

I noticed my ground wire came off, and that could be why it was overheating. I really would like to solve this, since I think I figured out that Constant power is used to save information/settings/power-off state. With the above rigged method it powers on into "Demo mode," which did not happen when it was installed in the previous vehicle.

Thanks :).

cx-7heaven
06-19-2009, 11:55 AM
Thanks for the helpful replies. I went out to check again and realized I made a mistake in my description. I have both the red and yellow power wires running from the head unit to the red/ACC from the harness.

I wasn't doing "trial and error" per se. It was an accidental connection. I knew both lines had the same voltage so I figured it was safe. This can be dangerous in general, I know.

I have come to 2 conclusions, which may be incorrect due to my limited knowledge.

1) Since the red incoming line has power, and my HU will still not power up with this only connected, both the Yellow and Red wires on the HU must be connected to power.

2) The "correct" wiring method did not work, but running both the red and yellow from the HU to the incomming red/ACC did work. I feel this implies the yellow/constant incomming power is not working. I cannot see any broken connections, so I'm leaning towards the harness being the problem.

If #2 above is correct, could I bipass the harness? If so, which color wire is the "constant power" in the factory harness? I notice Ford uses different colors for the other side of the adapter.

I noticed my ground wire came off, and that could be why it was overheating. I really would like to solve this, since I think I figured out that Constant power is used to save information/settings/power-off state. With the above rigged method it powers on into "Demo mode," which did not happen when it was installed in the previous vehicle.

Thanks :).

To bypass the harness, you will need a dmm or a test light. You first need to make sure which of the harness wires is carrying constant power, either the red or yellow. If you find one that carries constant power, you need to use your tool to test around on various leads in the car to find switched power. Your cig lighter is probably constant, so thats a no go. In my friend's Escape I used his A/C switched power, it is good sized wire, and easy enough to get to.