91-94 factory stereo wiring

[mr cribb]

Yeah, I have the factory amp completely unhooked .. so I crimped a wire from the blue (amp's remote on line) to the new amp .. from the new HU .. I thought that would work and save me some time .. but the amp isn't turning on with my new HU. It should be going straight from the new HU to the amp .. hell, maybe that's not the problem!

Right now my factory amp is powering up with the door speakers, but I may just get a four channel amp for the doors and a separate for the sub. Mine works with the factory stuff, but it’s nothing to write home about.

 

[trozei123]

i have an issue that probably will get solved fast. I have the basic walmart head unit and i also bought the scosche fdk4b adapter to make install easy. one problem i have is that all audio seems to play out of the "left channel" (if you had headphones, this makes sense) out of all four speakers. its kind of annoying, so I took a look at what I may have done wrong. there are two blue wires on the adapter. should the blue wire from the radio go to the solid blue or the blue/white wire on the adapter?

 

[mr cribb]

i have an issue that probably will get solved fast. I have the basic walmart head unit and i also bought the scosche fdk4b adapter to make install easy. one problem i have is that all audio seems to play out of the "left channel" (if you had headphones, this makes sense) out of all four speakers. its kind of annoying, so I took a look at what I may have done wrong. there are two blue wires on the adapter. should the blue wire from the radio go to the solid blue or the blue/white wire on the adapter?

sounds like you have the premium audio setup from the factory, that’s routed through the factory amp.
If that’s the case, then the fastest and easiest way would be to bypass it by disconnecting the amp and making all new speaker wires from your head unit.

 

[trozei123]

sounds like you have the premium audio setup from the factory, that’s routed through the factory amp.
If that’s the case, then the fastest and easiest way would be to bypass it by disconnecting the amp and making all new speaker wires from your head unit.

I figured out the wire I need is blue/white. I want to try to keep things easy in case I want to go back to stock. When I used the stock Hu, this issue was never there. I have even repurchased the new hu twice thinking it was a dud. They all did the same thing. Would bypassing the amp truly cure this "mono" problem?

 

[Mbrooks420]

I figured out the wire I need is blue/white. I want to try to keep things easy in case I want to go back to stock. When I used the stock Hu, this issue was never there. I have even repurchased the new hu twice thinking it was a dud. They all did the same thing. Would bypassing the amp truly cure this "mono" problem?

Are you sure it’s the correct harness?

When it first didn’t work, did you try any differences in how you wired it, or did you only swap in different head units?

 

[mr cribb]

I figured out the wire I need is blue/white. I want to try to keep things easy in case I want to go back to stock. When I used the stock Hu, this issue was never there. I have even repurchased the new hu twice thinking it was a dud. They all did the same thing. Would bypassing the amp truly cure this "mono" problem?

it could, but I’ve been out of the Explorer game for a while now, so I’m kinda rusty on the subject.

 

[trozei123]

This has me absolutely puzzled now. I've been living with this issue too long. I broke out my power probe to try and diagnose the speaker issue further. Here's all that I found.
1. The issue seems to be that the right side speakers are not functioning properly. Rf is on, but the sound is extremely low. Rr is so low that it cant be heard at all. The radio settings have not been altered at all. If I try to send the sound to each of those quiet corners, it doesnt work. This only is a problem with the new head unit. the factory unit has no issues with sound out the speakers at all.

2. Probing the harness, I get voltage on the battery hot wire and ignition hot wire. The ground wire also gets good ground. The individual speaker wires voltage and ground seem to change with the volume level which I assume is normal. This probing is on the adapter and the factory plug.

3. On the factory plug, there are two ground wires. One is a larger gauge than the other. The small black wire on my factory plug is in between a yellow/black wire and a green/yellow wire. Both of these wires have power, and mate up in the adapter harness to the battery hot and ignition hot wires. But there is no corresponding black wire on the adapter harness to mate with that small black wire. I assume that the larger black wire is for the actual radio while the small one maybe goes to the amp.

After these findings, I am more unsure if bypassing the amp will bring the right side speakers back to full power. I have returned and rebought a new head unit three times, but the issue still persists.

 

[Mbrooks420]

Are you sure the speakers just aren’t blown?

Have you tried more than one wiring configuration? Before and between swapping out multiple head units did you change any of the harness wiring?

 

[trozei123]

Are you sure the speakers just aren’t blown?

Have you tried more than one wiring configuration? Before and between swapping out multiple head units did you change any of the harness wiring?
[/QUOTE

Are you sure the speakers just aren’t blown?

Have you tried more than one wiring configuration? Before and between swapping out multiple head units did you change any of the harness wiring?

I can put the factory head unit back in and the speakers work perfectly fine. I did nothing to the factory wiring. I bought the adapter so I didn't back up the factory wiring in case I wanted to go back to stock.

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[Mbrooks420]

I’d guess at a bad harness, or you don’t have it wired correctly. If simply putting the factory heady it back in fixes it, there’s not much else it can be.

What’s the head unit model?

 

[trozei123]

I’d guess at a bad harness, or you don’t have it wired correctly. If simply putting the factory heady it back in fixes it, there’s not much else it can be.

What’s the head unit model?

I have replaced the adapter harness twice as well, but still same issue. Head unit is the basis walmart one for 20$. Adapter harnesses is the scosche brand for ford premium sound.

What I find off is that there is sound coming from the right speakers, but it's just low. I have even probed the speakers and there is voltage and ground on each respective wire.

 

[Mbrooks420]

There’s voltage but not enough wattage.

I can’t look up diagrams for $20 Walmart radio.

The only thing left is that you’ve hooked it up wrong. You need to correct your wiring.

Are you positive you have “premium sound”?

 

[damnford]

i h

There’s voltage but not enough wattage.

I can’t look up diagrams for $20 Walmart radio.

The only thing left is that you’ve hooked it up wrong. You need to correct your wiring.

Are you positive you have “premium sound”?

ad the same problem with my 90 Eddie and found out the fuse for the amp is the same fuse for the trailer wiring.

 

[trozei123]

There’s voltage but not enough wattage.

I can’t look up diagrams for $20 Walmart radio.

The only thing left is that you’ve hooked it up wrong. You need to correct your wiring.

Are you positive you have “premium sound”?

100% correct. I matched up every color on the radio harness to the corresponding color on the adapter harness. I even undid everything and matched the wires up one at a time to see if the problem would go away, but it did not. Same problem every time I try something different. Would bypassing the amp truly cure this issue?

 

[Mbrooks420]

i h

ad the same problem with my 90 Eddie and found out the fuse for the amp is the same fuse for the trailer wiring.

It wouldn’t be corrected by re-installing the factory radio.

 

[Mbrooks420]

100% correct. I matched up every color on the radio harness to the corresponding color on the adapter harness. I even undid everything and matched the wires up one at a time to see if the problem would go away, but it did not. Same problem every time I try something different. Would bypassing the amp truly cure this issue?

Not necessarily if it’s a wiring issue. You could run 2 new wires and it would certainly correct it.

 

[trozei123]

Not necessarily if it’s a wiring issue. You could run 2 new wires and it would certainly correct it.
[/QUOTE

Where would I run the wires to? I am just baffled by the fact that bone stock, everything works fine. With the new radio and adapter is where things get sour.

 

[Mbrooks420]

Something is wrong with the adapter, or the wiring. It’s the only thing that is logical.

You’d run wiring from the head units speaker output to the door. Bypassing the amp, at the amp, would work, but not if there’s an issue with the upstream wiring.

 

[trozei123]

Something is wrong with the adapter, or the wiring. It’s the only thing that is logical.

You’d run wiring from the head units speaker output to the door. Bypassing the amp, at the amp, would work, but not if there’s an issue with the upstream wiring.

How would I test the adapter harness to see if that is the issue? I figure if I run all the possible tests before firing the parts cannon would make solving this as pain free as possible. Probing the speaker wires at half volume gives me a reading of 6.2 volts. This number shows up on both power and ground wire on all four speakers. What should it be? Do you know on the factory plug what the second ground wire is for?

 

[trozei123]

How would I test the adapter harness to see if that is the issue? I figure if I run all the possible tests before firing the parts cannon would make solving this as pain free as possible. Probing the speaker wires at half volume gives me a reading of 6.2 volts. This number shows up on both power and ground wire on all four speakers. What should it be? Do you know on the factory plug what the second ground wire is for?

Wiring harness match
I took some pics of my harness that I am dealing with. Main pic is the one where I am holding the adapter against the factory plug. What I don't know is why there are two ground wires. The larger one matches the adapter harness ground. But the smaller one on the right side has a blank slot in the adapter harness. Is that small ground wire for the amp?