"and all the wires' coatings are crumbling off all the way down. i tried to wrap them individually,"
How competent are you at cutting wire and attaching connectors? A lot of people go for a replacement harness. But if you put aside a couple of hours to replace the wires individually, the job goes easily.

See http://www.brickboard.com/RWD/?id=678119

If you can't find teflon polytube, use the small diameter vinyl tubing found in hardware stores used for water. It is oil and heat resistant.


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1980 245 Canadian B21A with SU carb and M46 trans

You need a replacement harness from any 85 (non-turbo) 240 through 87. In fact I'm prety sure an 88 240 harness will work (I've laid them out side by side to compare), but has one extra connector near the ECU which will be unused in your application. It is entirely possible to do without moving the manifold although on a first run, I am not sure which way is easier.

thanks everyone for your advice. it's been very helpful.
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1986 244DL 189K 'Vickie'

Yes it is possible that it could effect some of the dash components and you do need to repair or replace it.. As for how hard is it to do.. well it is a job. I would be very careful in replacing it with a harness from the junk yard.. Make sure it is the exact one for your year and model, the junk people will tell you that a lot fo them work, which some do , but stick with what the people on this board advise you on... A later model harness will interchange in most applications but some reconfiguring might be needed.. If you have basic common sense you should have no problem.. Just mark everything and replace one section at a time so you do not get overloaded with wires hanging out everywhere.. If you need help just ask..Max
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Max..1989 244 DL 5 Spd., Bilstein HD, Turbo Swaybars, Poly Bushings all round, Turbo Wheels, Black leather interior, Electric mirrors, LED dash and gauge lights.

That is the engine wiring harness connection. From the way you describe it you need to worry or at least be more than a little concerned. Lot's of screwy electrical problems can crop up due to the crumbling insulation. Volvo did upgrade the part and the only real cure is to buy the later wiring harness for your model (expensive but good used ones can be had) or make one yourself.
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'80 DL 2 dr

That's the electrical connector that connects the engine wire harness to the body wire harness.
It has a alt wire, starter wire and the temp sensor wire. some others I'm sure.