bad wiring harnesses

[Adrian Thompson]

Sorry to keep asking dumb questions, but I keep seeing people talk about bad wiring harnesses. Is this a multi year issue, is there are start and end date to the proplem etc? What happens?

[SwedeSport]

85 16v turbo was the primary problem child. I am not sure if it affected 86 models as well.

It had something to do with the insulation on the wires. If I'm not mistaken they were soy based, and couldn't take the heat. Usually you find the engine bay harness is shot while the interior harness is ok.

I have the problem in my 85 900 T. But neither of my 86s have the problem. One is a 16v NA, and the other is an 8v NA.

[Geoff]

It happens on 8v cars but doesn't seem to happen as often as on 16v cars.
As Jason said, seems to mostly be 1985 model year only. The plant based insulation just crumbles or melts off the wires after years of being exposed to the elements.

[DrewP]

Both my '85's (16v Turbos) have had the harness under the hood and in the driver's door jam and some underneath the fuse panel fall completely apart, insulation flakes off.

I remember reading once upon a time that the trick was to just swap in an engine harness from an '86, same pin configuration on the ECU connector and all the same sensors, those didn't disintegrate. Never did find an '86 in a junkyard or put effort into finding one, we just pulled them out and repaired what was bad. When I have to move the harness out of the way or work on it I just try to be as gentle as I can.

[Jordan]

I think '86 harness actually is quite different from '85 in terms of plug locations. Seems to happen on almost all '85s I've seen and a few 86 here and there. Volvo's had the same issue.

[Adrian Thompson]

OK thanks guys, so this seems to be another reason to look for a later car.

[Crazyswede]

I think it is all models of 85. My 85 8v has a bad case of failed wiring insulation and my old 85 16v turbo was also bad. Just about every 85 I have ever seen has bad wires.