hi guys, maybe some of you know that i am trying to convert my notchie into fastback. I asked couple of people here for help but got no response. I already took the rear clip, lights, lid and a bumper off. What i'm concerned about is fastback light harness. does anyone have any pics of how to replace them? how do i take the old ones off. pics would be awesome. It would be even more awesome if someone could tell me how to do the whole thing with details, if not i will try to figure it out PS. lol i need to have my car ready by September 11th ( Fierorama) thanks, dominik
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04:06 AM
PFF
System Bot
Master Tuner Akimoto Member
Posts: 2267 From: South Florida,USA Registered: Jul 2003
If you get a fastback wiring harness the whole thing is nearly plug and play. You disconnect the nothcback harness at C500 and connect the fastback harness. It will be nearly completely obvious how to route it.
There is one pin change that you need to make at C500 or you won't have brake lights. I'm not sure to this day why it's not 100% plug and play but it's not. On the coupe wiring harness remove a white jumper wiring going from G7-H8. Then on the GT harness trace from brake lights and find a blue wire pined in at J9. Remove it from there and use the connector from the white wire and pin it in at G7. Here is the thread:
jscott1 said: There is one pin change that you need to make at C500 or you won't have brake lights. I'm not sure to this day why it's not 100% plug and play but it's not.
The notchbacks don't have seperate brake and turn signals. That jumper wire combines the brake and turn signal output for the notchback tail lights.
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07:45 PM
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
The notchbacks don't have seperate brake and turn signals. That jumper wire combines the brake and turn signal output for the notchback tail lights.
The part I don't understand is that my Helms doesn't show that jumper. It shows a 100% plug and play harness downstream of C500. Maybe somebody realized it wouldn't work after the drawings were made. But by the time the 88 books were printed you would think they would have worked out the bugs in the fastback wiring huh?
A/C switch is off on both cars. I'm making a fasty a notchy and a notchy a fasty. Both cars have the fan going when the key is turned on. One is an 88 and the other is an 85.
When I made the 88 a fasty, it was just a matter of putting in the correct harness to make everything work. Now going back to a notchy it's all messed up. I wonder if it's because I am using an 85 harness?
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10:30 PM
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
If you didn't touch the engine harness and only the taillight harness there is nothing to affect the fan. You have the wires for the lights, the cruise, and the trunk blower fan, (on the 85). Now that I think about it, the trunk blower fan might be linked into the radiator fan somehow.
However, the harness I used for my 88 coupe when I did my conversion also has the wires for the trunk blower, but my radiator fan does not blow all the time. But, I don't have the drawings for an 85 so I can't confirm the link. That would be my next move if I were you.
[This message has been edited by jscott1 (edited 07-03-2005).]
My 88 coupe has a V6 in it and I used an 86SE rear harness (had the trunk blower) and it worked fine. It was a long time ago when I did the fastback conversion to the 88, so I can't remember if I did anything.
Right now the 88 gets nothing to the rear lights except when I put the car in reverse. The reverse lights come on, but they blink with the blinkers if I turn them on. The blinkers also blink very slow when in reverse
I also noticed the 85 rear harness didn't have a ground to the chassis above the right rear tire and the 86 harness (from the 88) does.
The 85 fasty lights up the blinkers when I step on the brakes. If I turn on the blinkers they blink.
I'm stumped.
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11:04 PM
Jul 4th, 2005
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
It sounds like a real mess, I can't even begin to sort it out.
I would pull the harnesses off, get "new" known working good harnesses, and start over. Electrical gremlins are a paint to chase down, but most are attributed to loose connections or bad grounds though. If you mix in hacked up wiring you will never sort it out.
The Fiero taillight harness is pretty simple though. I didn't have any instructions and it was just sort of obvious to me how to route the thing. The only problem I had was the brake light thing I talked about earlier.
