early to late m20 c101 help

[TOOTHpasteTRACE]

I hope I've posted this in the correct section. Sorry if I haven't.
I have an 87 325is that I've swapped a 90 M20 into along with the wiring harness. After I wired everything up and turned the key over, I had a wire short and burn up. It's a red/yellow wire from the main relay to pin #20 on the c101. On the chassis side it's a brown wire in pin #20 which also burned up. The chassis side is still the stock harness. Haven't messed with it all. I've read I need to just cut that wire and cap it but won't that remove my abs? Any insight is greatly appreciated. This is my first BMW.

[TOOTHpasteTRACE]

I remember checking the relay and seeing 84 where the culprit wire plugs to but I believe the center pin of the main relay is supposed to be 87, correct? Could possibly having the wrong relay in cause the wire to melt like that?
I'd like to make sure before replacing the relay then testing and causing any further damage.

Thank you again for sharing any knowledge. I've tried searching for answers elsewhere so I apologize if this is a previously discussed subject. Perhaps I overlooked. If anyone has a link to a similar problem, I'll look there.

Thanks, Trace.

[rhE-30]

Serach here for the electrical repair manual, I think its abbreviated ETM. Its easier than it seems to get your answer from there.

[TOOTHpasteTRACE]

Thanks. That's cleared a lot up. Can't believe I didn't try searching this before for what seems to be a fairly common problem.