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Discussion Starter #1
I had this car for a couple of years and I have rebuilt the engine/trans and it would fire up and run crappy for a while. Then, I would not be able to start it when it was hot. The interior was mostly out of the car and I noticed that the ignition switch was bad, it was kind of dangling. Easy fix, still have the same problem. So, I start checking fuses and I found a burn spot where a fuse should be. I look behind the fuse box and saw that a wire had melted and also burned other wires next to it. The wire from the fuse box was burned all the way to an unknown box, its in the pic.

My first assumption was that the ignition switch was faulty, so they tried to "hot wire" a few things? Then I found an ECM with a code of GOF21??? I had a real problem trying to find what it actually came out of but I was expecting a A9L/P... I did pick up a A9P on a trade a while back, its supposed to be from an '89 MAF and I will use it for a MAF conversion, but I really just wanted to do this wiring without overly complicating it! I was going to fix the capacitors on my '93GT and I was going to practice soldering/desoldering on one of these boards first. I got enough capacitors to do a couple of these anyways.

By the way, Would this ECM cause this wire burn? I really didnt think that it would, but I should ask anyways. Thanks!
 

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The last pic didnt post. This is the ECM in question that came out of my '88GT and from the little info on it out there, it came from a '88 F150?
 

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I almost have the old harness out and the engine bay is the only part left. Is there a trick to getting the rubber grommet out of the fire wall?
 

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Ford isn't stupid about safety. Things inside the car wiring are very well protected either by fuses or by fuse links.

What they can't control is someone later sticking the wrong fuse in, moving wires, or removing fuse links. That burned spot should have a 15 amp fuse. A spot below it to the left is supposed to have a 5 amp fuse, and I see a 30 amp. That's another wire fire waiting to happen. Another spot should have a 15A and it has a 30.

With crap like that it isn't any wonder you are buying a harness.

The ECU won't cause the wiring to burn up like that if nobody has jacked the wiring all up or used the wrong fuse sizes.

What you have is a ticking bomb with all the oversized fuses installed, I mean you have a 30A where it should be 5A. That fuse feeds dash light wires. That's another wire melt waiting to happen.

The fuse all burned up just runs things like dash indicators, some modules, solenoids, and things. Once you melt one wire in a harness into another wire, which will happen when someone does stupid stuff with fuse size and you get a short, then all heck can break loose.
 

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Yeah, the guy that I bought this off of seemed really dumb! I just didnt expect this huge electrical problem because I was able to drive it on/off a trailer... So, do you think that this happened because of the fuses? The burn spot in the fuse box had a jumper w/o a fuse! I am hoping that I will be able to fix it with this new harness. It's kind of overwhelming because I have never been this far into the electrical system..
 

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Yeah, the guy that I bought this off of seemed really dumb! I just didnt expect this huge electrical problem because I was able to drive it on/off a trailer... So, do you think that this happened because of the fuses? The burn spot in the fuse box had a jumper w/o a fuse! I am hoping that I will be able to fix it with this new harness. It's kind of overwhelming because I have never been this far into the electrical system..
I'm glad you fished the harness out. I pulled my EFI harness but never the dash harness or the left side harness.

First thing is make sure you find every fuse or fuse link that moron messed up. Then if it blows a fuse of fuse link, you can look for what else he did on that line.

The melt down happened because there is or was an overload on that circuit and the fool hard a hard jumper across the fuse. I have a Ford OEM schematic up on my webpage but it is for my 1989. It should be very similar.

Be sure before powering it up you get all the correct fuses in. Also check the links up near the start relay at the common post where the battery connects, and make sure the negative of the battery has a chassis ground. Look at the "index" in this link.


Index of /1989 wiring
 
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Discussion Starter #9
This is from the harness that I pulled out of the car and I really cannot tell if the fusable links are damaged because they are enclosed... I looked up what part got burned and it was just the door chime if I am right. The last pic is a hack/splice job that was next to the steering wheel. My new harness is replacing all of this.
 

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This is from the harness that I pulled out of the car and I really cannot tell if the fusable links are damaged because they are enclosed... I looked up what part got burned and it was just the door chime if I am right. The last pic is a hack/splice job that was next to the steering wheel. My new harness is replacing all of this.
The black wire area is the fuse link, the molded plastic part covers a splice and just identifies the part.
 

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The last pic didnt post. This is the ECM in question that came out of my '88GT and from the little info on it out there, it came from a '88 F150?
Nope! Part No. is DC
Speed Density for a 1986-88 Mustang Auto.
Fuel Injection Technical Library » EEC Program Codes

The DC is the right one for '88 SD Auto.
A9P is for MAF Auto. You got the right one!

I still have the original DA1 which is for the SD manual.
The DA1 has a 1-piece case, where the A9L (Manual) has a 2-piece case.
Circuit boards are very different.
DA1 has been stored away for 20+ years, opened it up the other day to see what the caps look like. Everything looks brand new!
 
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I'm resurrecting this thread to get some clarification of the fuse box orientation & configuration for various years of the Fox Body.
My '88 is oriented like this & the hazard flasher is not in the socket. The wires coming out of the socket & going towards the rear are exactly like mine. The hazards work, the module is up under the dash somewhere, you can hear it "clicking".
Was this changed in later years? Or just many cars hacked up?
The reason I ask is I'm going to separate the fog lights from the main light switch which is very easy to do by installing an add-a-circuit in #8 which will now feed #15 location (no fuse). You only need to know which is the supply side to the fuses & the load side of the fuses. It gets confusing when up & down become left & right. I have verified with multi-meter. The add-a-circuit on eBay is $1.00-2.00.


 

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changed in '90

hazard flasher is on backside

signal flasher is up by the column
 

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OK. Why did they mount it on the backside when a socket was available?
Did they ever change the orientation of the fusebox, i.e. rotated?
 

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note sure on either

maybe space?
 
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