1987 M50 Swap Wiring Question.

[SkorcherX]

So I have been mapping out the wiring of the M50. Trying to get everything thats needed from the X20 plug re-pinned to the C101 plug.

I feel like I am missing a number of things from the C101 plug. I have been scrolling through these wiring diagrams from wedophones.com for a couple of hours now and I think I am going cross-eyed!

Please don't tell me to use the search function or read the comprehensive swap sticky. Trust me I did. Both yielded the advice of studying the wiring diagrams, so that's what I have been doing, and I could just use a couple of bones thrown my way.

[e30rapidic]

this is what I used on my 87 with an S50

C101 m50
1 ------ 25
2 ------ 1
4 ------ 12
5 ------ 23
6 ----- 22
7 ------ 21
10 ------ 2
11 ------ 19
12 ------ 8
13 ------ 13
18 ------ 18


you need to get speed sensor from C104 plug under dash

[nando]

sometimes the E36 oil pressure switch is brown/yellow, brown/gray or brown/green..

but otherwise it looks OK to me

does the '87 not have an unloader relay?

also, you'll want to hook up the VSS input and tachometer. they might be in an auxilary connector on the '87.

[e30rapidic]

does the '87 not have an unloader relay?

that's exactly how mine is hooked up - sans any issues

1 blue alternator
2 green/yellow oil level (static)
3
4 brown coolant temp
5 brown/green oil pressure switch
6 green/white fused power O2
7 green ignition coil
8
9
10 blue oil level (dynamic)
11 white/green service lights reset
12 grey CEL
13 green/violet fuel pump
14
15
16 white/black SRS (unused)
17
18 black/yellow starter
19
20

also, you'll want to hook up the VSS input and tachometer. they might be in an auxilary connector on the '87.

wire that goes to pin 24 on the x20 goes to the red/yellow wire of the c104
wire that goes to pin 14 on the x20 goes to the black wire of the c104
wire that goes to pin 20 of the x20 goes to the wire on the back of the instrument cluster in the circuit board with the green covering that snaps onto the cluster.

[SkorcherX]

So wait... There are wires in the glove box that come off the C104, which need to get pinned to the C101?

For some reason I was thinking that the wires going to the C104 were not coming from the C101. Sanity check please!

[nando]

you have to connect them to the E36 harness somehow. Whether that's through the C101 or by some other means, that's up to you.

[scottinAZ]

I connected my wires on the C104 through a branch on the swap harness. I took the original wires off the M20 harness, lengthened them, and branched them into the swap harness at C101. easy money....