ONE wire left! tell me where this thing goes

[LooN]

Put a new wiring harness in my VANOS M50. Before I started, the extent of my mechanical knowledge consisted of how to change oil and replace a flat tire, so bear with me.

I am now down to ONE WIRE that isn't connected before I can put the manifold back. At first I thought it was for the starter, but it turns out it wasn't (wire isn't black/green or black/yellow).

Here is a pic. From my camera phone so sorry if the pic resolution is bad. The inside wire color is BLUE. Anyone know where this goes?


Some more info:
The harness I got was SUPPOSED to be out of a '93 325i manual w/out ASC, but from what I've seen on the boards it seems like it is an S50 harness. It also doesn't match the BMW TIS software diagram for an M50--relays come out of driver's side and the OBDI engine diagnostic plug comes out of the passenger side, as well as a few other differences in wire placement. Doesn't matter to me as long as it works, which I think it should.

Thanks in advance!

[equate975]

would be more helpful if you showed what harness it went into.

[LooN]

It comes out of the main engine harness, same place the two small starter wires and all the sensor connectors come out, underneath the manifold.

[EtaSport]

You'll have to trace where the wire leads, maybe do a test with an ohmmeter for continuity at pin 25 of your x20 and the end of that wire. I believe its the alternator charge indicator. Thats the only blue wire I know of. If you have continuity, then it is that one.

If no one figures it out, I'll check the etm tomorrow.

[Skafrog]

alternator

[LooN]

I did a continuity test with the ohmmeter at every pin on the DME plug and nothing, but i'll check again...alternator you say? I'll look into it and post progress...thanks!

[matt]

It's the alternator... it doesnt go to the DME, it goes to the C101. It's for your alternator light on the dash.

[LooN]

OH jesus i just nearly a heart attack. I discovered that the two terminals on the alternator had no wires connected to them so I connected the blue wire to the D+ and then connected a fatty red wire from the starter to the B+ post on the alternator. I thought I had everything in order so i did a quick doublecheck then reassembled everything and reconnected the battery.

I got in the driver's seat and all the interior electrical systems seemed to be working--gauge cluster, windows, lights. I then took a leap of faith and turned the key all the way...and with a loud SNAP everything went out. Turned the key halfway again and nothing. No lights, no functional electrical systems anywhere on the car. I wanted to kill myself.

So i decided to eat a candy bar and smoke a cigarette and put it all in perspective: I didn't burn down the house, I didn't squander the family nest egg, I didn't kill anyone. It's just a car. Life will go on.

When I came back in the garage, i noticed--yes, is that--the interior lamp was ON! AHH it's not dead! Back to the way it was--lights, windows, gauges work. But I'm not about to turn that friggin key again.

Anyone know where to start with this? I'm thinking checking all the main power wires in the engine--anyone have a good reference for this? Thanks guys for all your help so far it is MUCH appreciated!

[KangamangusDriver]

There are two wires running from the positive terminal of your battery.
One is thick, one thin.

The thinner wire is fused. Follow it from your battery onward and you should find a fuse. Start there. I believe that wire is for your fuse box and or accesories besides the starter.

Good luck!!!!!

[a32guy]

Were all the heavy gauge cables tight? Also the battery cables? This can happen if a terminal on the battery isn't tight. Then once you move it a bit, everything comes back. Check that everything is tight.

[sky_captnE30E36]

That wire that you werent sure about looks awful simular to the VANOS ground wire, connects to the bolt on the front lift hook

[golde30]

That wire that you werent sure about looks awful simular to the VANOS ground wire, connects to the bolt on the front lift hook

i was thinking this same thing.

[matt]

You're both wrong. It's for the alternator. The ground on the vanos comes out of the fuel injector box.

If you're going to bump a thread from 6 months ago, atleast be right.

This is where FredK comes in and quotes that last part in his sig. :giggle:

[FredK]

Haha!

The tip off should have been BLUE wire. The injector rail's ground wire is brown after you peel back the heat shrink or whatever black tubing they put on it.

My harness for some reason was cut right at the blue wire so I had to solder on a lug so I could connect it to the alternator.

Anyway, only a year ago I was in these same guys' shoes. I didn't know crap about how to wire up an M50. But, with the assistance of r3vlimited, I was able to get my swap up and running. I did not ask what brake booster to use though.

Now, for those people that incorrectly answered "fuel injector rail ground," your punishment is to run pink bottlecap wheels for a week. ;-)

[LooN]

Funny that someone bumped this now.. To give everyone some closure, turns out that all my wiring was correct. The engine was seized, scored two cylinder walls cranking the thing so much.I still have the block if anyone is interested, heh

I ended up buying an m50 from h0lmes and swapping it in. Just got it back from the shop a couple weeks ago...Car runs beautifully :)