I am doing a notchback to fastback conversion and need help to switch the wiring harnesses. As i am trying to do this in as short of time possible(trying to be ready for the Daytona Turkey Run car show), I would like help so that it is rather painless,at least as much as that amounts to working on fieros.

What are you starting out with?
If it's a Formula, the GT harness is pretty much plug'n'play. (Been there, done that.)
If it's a base coupe, you won't have any brake lights. You'll need to add a wire for the brake light circuit in the GT tails. (Easiest place is probably the high mounted center brake light, but I don't know that for sure.)

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Raydar
88 4.9 Formula IMSA Fasback..........................88 3.4 coupe -soon to be something other than red

Read Nealz Nuze! Praise the Lowered!

I am starting with a base coupe. I know it is possible to wire it in as I have seen the results.

There is only one wire that has to be changed to make the brake lights work. Other than that it's plug and play.

Mind elaborating there jscott? Knowing which wire(color if it has one) and where to wire it too will help alot.

[This message has been edited by 88Slayer (edited 06-22-2008).]

quote Originally posted by 88Slayer: Mind elaborating there jscott? Knowing which wire(color if it has one) and where to wire it too will help alot.

Okay it's been years since I did it, and I've slept since then, so it's tough to remember, but I'll give it a try...

I think you have to physically remove C500 from the side of the car to see this, I'm not sure anymore. But if you look at C500 and you see a white wire connecting G7 to H8. (There is only one such wire) Cut that wire.


I know with all the goo surrounding the wires I had a hard time figuring out which one was J9. What you want is a jumper between the two pins J9 and G7. You can hard wire it if you want and not worry about re-pinning the connector, that's what I did since I'm never taking it apart again.

Like I said I had a hard time finding J9 so what I did was put a broomstick on the brake pedal, (which made G7 hot with 12V) and put a safety pin on the wire and stuck it in all the white wires until the brake lights came on. Then I just made a hard connection between those two wires. That's all there is to it.

I tried finding a good diagram of C500 in the archive but this was the best I could do, (I hope it helps)

battery side............trunkside

left..................right
top...................top
j 6 7 8 9...........4 3 2 1 e
h 6 7 8 9.............3 2 1 d
g 6 7 8...............3 2 1 c
f 6 7 8 9.............3 2 1 b
...................5 4 3 2 1 a

Here is a pic:



To remove the pins, take the snap on cover off, then find the white strip of plastic. This has tines like a fork that slide in and hold all the pins in place. Gently pry this plastic strip out and pull it out, then with a paper clip the wires will come right out.

This thread might help me figure out why War Hammer's brake lights don't work. We didn't switch tail light harnesses, we just snipped, clipped and stripped......the wires you pervs! lol Anyway, basically just swapped out some of the coupe sockets for the GT sockets. Got the parking lights, turn signals, and four-ways working. But the brake lights don't work. Could this be the reason why? I'm not 100% sure, but I don't think the third brake light's working either. Sorry Slayer. Don't mean to highjack your thread. But maybe answers on both your's and my problems could help us both.

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Whade' "The Duck Formerly Known As Wade" Duck
'87 GT Auto
'88 Ferrario
'84 Indy

[This message has been edited by whadeduck (edited 06-22-2008).]

Hey if it helps it aint hijackin'. That diagram should help alot when I start the rear swap. Need to order some new taillights first though.

quote Originally posted by whadeduck: I'm not 100% sure, but I don't think the third brake light's working either.

The third brake light is on a totally different circuit, so I don't know what would happen to make it not work. unless you inadvertently shorted something together.

I'm curious myself. Because I think we tried the lights before we started swapping out sockets, and they didn't work then either. We swapped out the brake light switch for the one on his other '88 coupe and that didn't do anything. We tested it and the brake lights worked on that one. My goal is to get the brake lights and the others all working for Paul before he comes back from Ohio. He's getting eight stents put in and I think it'd make him relax a little once he got back and knew that everything was working on his car.

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Whade' "The Duck Formerly Known As Wade" Duck
'87 GT Auto
'88 Ferrario
'84 Indy

Allright, time to dust this thread off as I am now about ready to rip the top half of my car into pieces for my t-top/fastback conversion. IS that wiring diagram of the stock coupe plug guru? and if not, then I am sure I shall somehow mess up on pulling the GT harness out.

wiring diagrams are your friend...

Cut the wire that goes from C7 to H8 on the C500


You will need to run an extra wire for connecting to "B"


Connect as shown


Note: the turn socket differ from the brake light sockets - however you can turn the brake light socket into a turn one by removing the wire from the socket - they open up like a clam shell and you just simply remove the one wire. Been some time since I did this, so I don't remember which wire to remove from the socket, but it should be self explanitory once you look at the bulb and then the socket and see which contact you need to keep.

Do this before you put the rear clip and bump cover on - that way you don't have to work around them, actually the clip is not too bad, but you have to remove the rear bumper cover IMHO to do it correctly.

Of course, if you just have the GT wiring harness - just plug it in (you may have to make a change in the connector, but try it first).

Well I have mostly succeeded in taking off the GT light harness. As I have just figured out,I shall not be using at least 2 of the connections as I have no wanting of putting in the trunk fan motor/relay. Now then, there are 2 plugs at the end of the tail on the harness. What exactly do they control?

quote Originally posted by 88Slayer: Well I have mostly succeeded in taking off the GT light harness. As I have just figured out,I shall not be using at least 2 of the connections as I have no wanting of putting in the trunk fan motor/relay. Now then, there are 2 plugs at the end of the tail on the harness. What exactly do they control?

I am going to take a "guess" that they are for the cruise control - but that is just speculation.

Aye Moose, it does look like at least 1 of those is for cruise control.