Wiring harness repair on a 86 GT-S

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Wiring harness repair on a 86 GT-S

Postby povertymobile » Tue Jul 05, 2016 10:24 am

Hello Everyone,

Let me give a little background. I got this AE86 back in November of 2013. I was planning on getting a swap through a shop but the plans fell through. So I got the car back from them about a year ago. When I got the car back it ran. It was not great but it would turn over just fine. Weird stuff would happen like the drivers side headlight would continually go up and down.

Okay so now flash forward to couple months back. The car will not turn on. I've tried to turn the car over and it will just crank. I changed the spark plugs, tested the resistance in the wires (which was in acceptable ranges), also I could smell gas on the plugs so I think the EFI system is working fine. I tried to perform a spark test (this was my first time) and it did not look like there was a spark that I could see.

Also none of the lights on my dash cluster were working properly. The battery indicator would not go away from the dash & I tried two different batteries that work fine in my coupe to be sure it wasn't related to that. Other weird stuff included the right turn signal getting stuck lit up on dash cluster.

Anyway, I spoke with a friend who has some knowledge of AE86's and he told me that it's likely my wiring harness. I went ahead and removed the dash harness to start out. I have it out now. Now I have some knowledge of soldering electronics so I thought I'd try to fix it on my own. I took a look at the end of the toyota shop manual for the 1986 Corolla, and it has a wiring diagram. I'm not having much luck with figuring out what controls what and where I should be looking for a broken connection.

I was wondering, does anyone have any resources or advice that could help me out? Any help would be appreciated. Alternatively, does anyone know of a company or an individual that could possibly repair the harness for me? Thanks for the help. Looking forward to get through this wiring trial so I can use this car!

Edit: Wanted to add some additional information. The harness has a lot of electrical tape all over it which leads me to believe the previous owner cut. Also, I've never driven this car more than up and down the street so it has been sitting most of the time. I was thinking about starting to remove the tape and seeing if I can find any issues. However this looks like a quite a task so I'm wondering if there are any specific places I should be looking first. Thanks for any help.

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Club4AG Expert
Posts: 354
Joined: Mon Jan 14, 2013 9:43 pm

Re: Wiring harness repair on a 86 GT-S

Postby shagymc » Tue Jul 05, 2016 7:40 pm

Honestly, the first thing I would do anytime thecar is acting screwy ischeck and re check all the grounds. take any rust off, run new wire to different ground points (I.E. Block to chassis, etc...). Once that is done, slowly remove tape but take detailed pictures of everything. You don't want to remove stuff and not know where it goes. Repairing a harness can be tedious but it isn't hard. Just go slow and do it right. You may even want to remove sections and inspect and if it looks good, re tape with new tape so you keep it together and you know what you've looked at and haven't. Good luck!

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