Electrical 1986 GT- mystery wire near starter relay

NIKwoaC · Mar 19, 2018

Some of you may have seen me post this in my progress thread, but either way I'm looking to get more eyeballs on this.

I'm rewiring some things and doing some wire hiding at the same time. Came across this connector hidden in some tape. Wire jacket is black with a white or gray stripe (it's faded, so it's hard to tell). It comes off the main EFI harness, near the starter relay. It's adjacent to a power supply line, the small ground connector that ties directly into the negative battery cable, and a relay of some sort that I have also yet to identify.

I've been looking at wiring diagrams but I'm struggling to find anything that makes sense here. Hoping the Stangnet knowledge base can help me out before I spend the time tracing the wire back through the entire harness to find the source.

Thanks dudes.

Blown88GT · Mar 22, 2018

That type of spade terminal & the fact that the main wire color is black would suggest it's a ground for something.

Noobz347 · Mar 22, 2018

lol

The only ground that I see in the shop manual that comes off of the main engine harness is the EGO ground and it goes to the back of the block on the passenger side.

Derp... Here's the image.

If it's coming from the harness that is [not] the fuel injection harness then it may be this one:

Looking back at your description and image, I think the cutaway might be the one you're looking for.

Edit: Combined my posts into one.

Blown88GT · Mar 23, 2018

Noobz347 said:
lol
... it may be this one:

Looking back at your description and image, I think the cutaway might be the one you're looking for.

Good find! It looks exactly like the one the OP shows.

Noobz347 · Mar 23, 2018

Blown88GT said:
Good find! It looks exactly like the one the OP shows.

By the way, my chuckle was because your response was exactly what I said in his build thread. hehe

Had to break out the manual because I guess he wanted a little more detail.

NIKwoaC · Mar 24, 2018

Noobz347 said:
lol

The only ground that I see in the shop manual that comes off of the main engine harness is the EGO ground and it goes to the back of the block on the passenger side.

Derp... Here's the image.

If it's coming from the harness that is [not] the fuel injection harness then it may be this one:

Looking back at your description and image, I think the cutaway might be the one you're looking for.

Edit: Combined my posts into one.

Hmm... What manual did you find this in? My car does not have this circuit breaker. I did some digging though, and it SOUNDS like, the wire is actually a power supply wire for optional features like electric windows, convertible tops, or power locks. My car is not a convertible, but it does have power windows and locks. In fact, if you look at the wiring diagram for the power door locks, the supply line is a black wire with a white stripe.

But... My power locks work, despite this wire not being connected to a power source. At this point my hypothesis is that, since one of the POs had an alarm system installed that is still in the car today, the power locks get power from some other source through the alarm... Which would have rendered this wire useless, and maybe it was disconnected by the alarm installer.

I can't seem to find a power window wiring diagram for the '86 and older cars, anybody have one of those?

Noobz347 · Mar 24, 2018

jrichker · Mar 24, 2018

Try this....

See http://slantnosefox.com/picturehosting/jeremy/86 electrical & vacuum troubleshooting manual.zip you can download the whole set of electrical troubleshooting and diagrams for an 86 Mustang courtesy of Jeremy, AKA V8only.
It is a big 61 MB download that you get to unzip and save on your computer. It may take some time to download it, but the results are worth your time.

NIKwoaC · Mar 25, 2018

jrichker said:
Try this....

See http://slantnosefox.com/picturehosting/jeremy/86 electrical & vacuum troubleshooting manual.zip you can download the whole set of electrical troubleshooting and diagrams for an 86 Mustang courtesy of Jeremy, AKA V8only.
It is a big 61 MB download that you get to unzip and save on your computer. It may take some time to download it, but the results are worth your time.

Awesome resource, thank you sir!

Jarhead67 · Jan 29, 2019

The wire in the cut-away is the mystery wire. I have the same issue, it was not connected to anything when I got the car. The cut-away makes no sense because it has it connecting to a circuit breaker from the starter solonoid. Does anyone actually have this wire connected to anything.

Please don’t show another wiring diagram, I need a picture from a real car showing where it’s connected.

Thanks

Rdub6 · Jan 29, 2019

Jarhead67 said:
The wire in the cut-away is the mystery wire. I have the same issue, it was not connected to anything when I got the car. The cut-away makes no sense because it has it connecting to a circuit breaker from the starter solonoid. Does anyone actually have this wire connected to anything.

Please don’t show another wiring diagram, I need a picture from a real car showing where it’s connected.

Thanks

I have an 86 as well. Same loose wire as you. I researched this before, and I have another wire going to my battery with an in line breaker that I believe took the place of that original breaker. I’m at work, but will take a few pics when I get home. Hopefully it will help.

Jarhead67 · Jan 29, 2019

Rdub6 said:
I have an 86 as well. Same loose wire as you. I researched this before, and I have another wire going to my battery with an in line breaker that I believe took the place of that original breaker. I’m at work, but will take a few pics when I get home. Hopefully it will help.

Thanks for the response. That little bugger has a lot of us confused.

Rdub6 · Jan 29, 2019

Tough to see, but the silver circled in yellow is an in-line breaker. That wire goes from the battery through to firewall to some relays under the seat which I believe control the windows and door locks.

I’m pretty sure that took place of the breaker that used to be connected to the solenoid.

We’ve revived an old thread, but hopefully that helps, or someone else comes in with a better answer!

Rdub6 · Jan 29, 2019

Here’s a pretty good pic I found on the web of what the original wiring looked like. I circled where the mystery wire used to attach.

Jarhead67 · Jan 29, 2019

Rdub6 said:
Here’s a pretty good pic I found on the web of what the original wiring looked like. I circled where the mystery wire used to attach.

Someone f

Rdub6 said:
Here’s a pretty good pic I found on the web of what the original wiring looked like. I circled where the mystery wire used to attach.

I can't believe it; YOU FOUND IT!!!!!!!!! It's not a ground after all, but I guess it doesn't need to be connected because everything works.

I hope this thread helps out some equally confused novice like me. Thanks Rdub6

Rdub6 · Jan 29, 2019

Jarhead67 said:
Someone f

I can't believe it; YOU FOUND IT!!!!!!!!! It's not a ground after all, but I guess it doesn't need to be connected because everything works.

I hope this thread helps out some equally confused novice like me. Thanks Rdub6

No problem. I’m curious, do you have another wire like I do that looks to have been added on and not from factory?

Jarhead67 · Jan 29, 2019

Rdub6 said:
No problem. I’m curious, do you have another wire like I do that looks to have been added on and not from factory?

I'll take a look tomorrow before work. Is it in the same area?
It's tough when we get these fox body's after 30 years of hack jobs by PO's.

Noobz347 · Jan 30, 2019

How odd that it looks unusually like the one in the diagram.

Jarhead67 · Feb 8, 2019

Noobz347 said:
How odd that it looks unusually like the one in the diagram.

Yeah, go figure

Electrical 1986 GT- mystery wire near starter relay

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Electrical 1986 GT- mystery wire near starter relay

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