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Electrical Wires found behind radio

  • Thread starter Thread starter Dkennie
  • Start date Start date Feb 3, 2024
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Dkennie

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  • Feb 3, 2024
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I found these group of wires behind my radio. 89GT not sure what they plug into. Can someone please help me if you have seen these before.
 

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91AOD5.0LX

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#2
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“A” and “B” are your factory speaker wire harnesses. “C” and “D” are your radio speaker and power harnesses both plug directly into the rear of the factory radio and “E” is your AMP input or output harness that plugs into the factory AMP if the car has the premium option. The Amp, if equipped and not missing, is located behind those wires.
You should also have an antenna cable laying around those wires which plugs into the rear of the factory radio. The Antenna cable can be seen in the attached photo which shows also the Amp.
Others please correct me if I’m wrong but until then I hope this helps to get you started.

 
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AeroCoupe

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Follow the wiring harnesses back far enough and you can remove the factory amp wiring and be left with just the two plugs that have 12V+ batt, ground, accessory 12V+, illumination, and speaker wires. At least this is what I did on my 93 Coupe and a few other Mustangs that I wired back in the day. This allows you to use just the simple wiring harness adapter kit to install an aftermarket head unit vs buying the one that bypasses the factory amp. Less wires are less headache.

The door and dash speakers are wired in parallel so bypassing the amp like this will still get you sound out of the dash speakers. One thing you need to note is if you reuse the factory wiring you will need to pay attention to the ohms of the speakers if you are replacing them. Best thing I can tell you to do is put a 99 mF cap on the positive lead of the dash speaker and use 4 ohm speakers. This will only load the head unit or amp with a 2 ohm load on frequencies 800 Hz and above which will not be hard on the head unit or amp.
 
Last edited: Feb 4, 2024
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Mustang5L5

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As others said, its the wiring for the factory amp but looks like it's been unplugged or the amp has been removed.

You can grab all that wiring and pull it out leaving the two main harnesses left. Since this is an 1989, pulling the amp harness from the 87-89 cars also removes the OE wiring for the door speaker to the radio.
 

Mindseye007

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Mustang5L5 said:
As others said, its the wiring for the factory amp but looks like it's been unplugged or the amp has been removed.

You can grab all that wiring and pull it out leaving the two main harnesses left. Since this is an 1989, pulling the amp harness from the 87-89 cars also removes the OE wiring for the door speaker to the radio.
Click to expand...
Wonder how many rms that factory Amp is ?
 

Mustang5L5

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Mindseye007 said:
Wonder how many rms that factory Amp is ?
Click to expand...

I don’t know how many the 87-92 amps have, but the 1993 amp was 80 watts
 
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Mindseye007

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Mustang5L5 said:
I don’t know how many the 87-92 amps have, but the 1993 amp was 80 watts
Click to expand...
All I remember is the factory cassette radio with the amp and stock speakers sounded amazing and had pretty good bass. I went to a beach called wassaga when i first got my 1991 mustang LX coupe 5.0 with a few buddies I had AC/DC girls got a rhythm cranked while cruising along the beach and some big boobed girls in bikinis waved at us and started dancing shaking their boobs so sweet lol..never forget those days.
 
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4cylredfox89

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Thought I'd post my radio wires here as well, here I have an aftermarket radio done by my foster brother back in high school when he was junior with his two buddies.

Now I believe I wired it up wrong a half year ago after trying to reconnect the wires where I thought they had went. Initially my sound would cut in and out over bumps in the road, so I pulled the radio and some more wires became undone...

I took out my radio again here is an image below, I found that both grounds were connected to each other.. I have no clue how this goes with these wires looking like this.

Later on would have intermittent no acceleration at lights,not sure it was related but this is what I'm tackling now to see if this resolves.

Can you please help me on what's going on here. Thanks!!
 

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Noobz347

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Wut? That's not Fak-Tree?


It's hard telling what all you got going there. How good are you with a multi-meter?

I mean, I can refer you to some wiring diagrams but I also see a lot of wire in there is [extra]. So, I don't know how much help that is going to be.

It should be easy enough to identify the speaker wire pairs. Pull the speakers and make a note of the wire colors. From there: Use the multimeter to identify the constant power and Ignition power wires.

That's pretty much all you need. If you still have a factory Fox amp in the car, pull it and toss it in the trash.

You need [Power] [Ignition Power] [Ground] and [Speaker Wires] and [Antenna Coax] to run any radio you want.
 
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