M30 Swap - Electrical Gremlins

[talltorontoguy]

M30 is in, engine runs. M30B35 (E34) into an 88 325 using M30 engine harness.

I have some electrical gremlins I'm trying to sort out. I have no idea where to start on this one...Windows only work if engine is off.

Any assistance or pointers on this one would be greatly appreciated.

Rod

[chadthestampede]

1. Windows only work if engine is off.

I have more or less the same problem, except my windows dont work at all.

[talltorontoguy]

Got to the bottom of a couple of things: Fixed the pinouts on the C101 connector to get the fuel economy gauge working. Indicator light problem also went away.

Brake lights coming on when clutch depressed seemed related to a loose pedal assembly moving just enough to trigger the brake circuit when clutch pushed in.

Still have the issues with the the heater fan and windows. Sometimes light up and work, sometimes not - car running or not... must be a loose connection but where? I think this is the unloader circuit but not sure how to troubleshoot.

Thoughts?

[george graves]

Must be the unloader relay. The windows motors get constant ground on both wires. It's only when you press a button it gets 12v to one wire or the other. That is after ACC. HTH

[talltorontoguy]

So the relay itself is bad? Any way to test this?

[talltorontoguy]

More info...

Pulled the unloader relay K5 (furthest left, closest to DS fender when looking at fuse box). Bridged pins 87 and 30, and the windows worked whether the car was running or not.

Then swapped relays, but had same issue... so that rules out the relay and any wiring past the fusebox to the windows. That leaves the wiring going into the fusebox.

I found this on E30 zone...

"To get the electric windows and sunroof to work with the doors shut and for the heater blower to work at all you need to connect the black and green wire from pin 15 on the E30 C101 to a small spade connector on the starter motor."

"There's a black/green wire from relays K5 and K7 in the fusebox, which goes, via the C101, to the smallest terminal of four on the starter motor. If the starter motor only has three terminals, then connect it to the strap that goes between the solenoid and the starter motor body."

I checked the starter and there are 4 terminals, and a green/black wire is attached to it (as part of the M30 harness).

I checked Pin 15 on the c101 plug and the wire is brown/black on the E34 harness (engine) side, but green/black on the fuse box side.

Now what?

My heater blower motor is working fine... the unloader relay is supposed to control both the windows and the heater fan... WTF?

Rod

[Garageaholic]

You might want to try to see if all of your wires are properly hooked up to the Starter. You should have 4 wires going to the starter. the thick main power wire (obviously), then you have the Black/yellow wire (signal for starter), the blue wire (alternator wire) and a black/green wire, which goes to ground (for all intents and purposes). That bl/gn wire goes directly to the unloader relay K5 in the car. That could explain why the windows work only when the car is off.... because you don't have that wire grounded... and the unloader relay isn't completing the circuit.. I've had the same problem until I realized this.

It is on pin...15 on the C101 port. Please track down that wire. and make sure you have ground to it. On the 735i engine wiring harness, it is the park/neutral wire, so you will have to do some creative wiring.

Also, shoot me your email address via my address (frank.macaluso@baesystems.com). i will give you a wiring diagram for the C101 port. It could help you out a bunch in diagnosing most if not all of your electrical problems at the source.... Hope to talk to you tomorrow...

[Funkmasta]

"To get the electric windows and sunroof to work with the doors shut and for the heater blower to work at all you need to connect the black and green wire from pin 15 on the E30 C101 to a small spade connector on the starter motor."

Rod

This is your problem for the windows. I chased this issue for almost 2 days a few weeks ago on a customer car. (we put an 87i motor into an 88i car)

[Funkmasta]

The green wire on C104 must go to switched 12V to activate the main relay. You can pick up switched 12V at the coil terminal 15. This will allow the main relay to turn on and the fuel pump relay to get energized.

The windows going up and down have nothing to do with the main relay turning on or not. It is the difference in the way the unloader relay is triggered between 87 and 88+ vehicles.

Both the 87 and 88+ cars have C101 pin 18 occupied. It connects the ignition switch to starter through the firewall.

87 cars don't have C101 pin 15 occupied. 88+ cars do.

C101 pin 15 is the unloader relay control on 88+ cars. When it is activated it interrupts the power to the blower motor, power windows, and some other stuff inside the car so that electrical system is completely unloaded during start. On 87 cars, the unloader relay is actuated directly by the ignition switch at C101 pin 18. Right now your car is in an always unloaded state.

In order to get the windows and blower motor working, add a pin to the C101 at Pin 15, and connect it to terminal 50 on the starter.

from another post... same issue

[talltorontoguy]

Thanks a lot for the information. Here's where I'm confused....

1. The windows don't work when engine is running, but the heater fan does. If I'm understanding correctly, they're both supposed to fail at the same if the issue is connecting pin 15 to the starter.

2. My M30 is from a 92 E34, car is 88 325 vert. There is a green/black wire already attached to the smallest terminal on the starter... which is probably why the heater fan is working.

Should there be two wires attached to the starter? Is there another place that the wiring could have failed on the windows circuit? Perhaps it's unrelated?

Last question is... when I run wire from starter to Pin 15 on C101, do I cut the wire that is there already (disconnecting it from wherever it goes) or do I splice into it as a "T".

Thanks for your help guys.

[Funkmasta]

that is weird. In our case it was just the one wire and they both started working. did you unplug the window lock button?

[talltorontoguy]

This is getting really annoying.

I cut the brown / black wire on pin 15 on the C101 connector (the E34 engine harness side) spliced a wire onto it and ran it to the smallest terminal on the starter (where the green and black wire already resides).

Windows still didn't work with engine running, but do with engine off. Anybody have any ideas?

[talltorontoguy]

Problem Solved:

On the advice of another board member I put a new splice into Pin 15 again at the C101 connector and ran a wire direct to ground. The windows worked whether engine running or not (they also worked if I pressed the button while the engine was cranking - not a good thing).

So - I put a new connector on othe end of the wire and ran it from pin 15 on C101 to the top terminal on the M30 starter (8mm nut) where the green/black wire is resident.

It worked. So... I guess one of my connections wasn't solid to begin with and this was the cause of my problem.

End result is:

Splice into C101 at Pin 15 (brown/black wire). Run wire to small top terminal on starter. Make sure you have a good connection.

TTG

[Doughnut]

Problem Solved:


End result is:

Splice into C101 at Pin 15 (brown/black wire). Run wire to small top terminal on starter. Make sure you have a good connection.

TTG

In the post before you said this didn't work? From wiring schematics I've been reading it says that pin 15 brown/black wire on c101 is "park/neutral input" for the auto inhibitor switch? are you using an auto harness by any chance?
And which terminal on the m30 starter? The positive small terminal on the starters solenoid or the earth side?

If you can help would be great and much appreciated, I begin my engine swap tomorrow! :o

[talltorontoguy]

It didn't work the 1st time I tried it because there was a faulty connection. Once I rewired it, it worked.

On the C101 connector, engine harness side, pin 15 is a brown/black wire for neutral switch. On the C101 connector, chassis side, pin 15 is a green/black wire which connects to the K5 relay in the fuse box.

I cut the brown wire about 3" from pin and spiced into it, ran the wire to the starter.

On the starter there are 4 terminals. 2 side by side with 13mm nuts; 1 on top with 8mm nut, 1 on bottom with 10mm nut. Connect the wire to the TOP terminal on the starter (8mm nut), in my case there was already a green/black wire attached there and I left it there. The bottom terminal should have a black/yellow wire connected (IIRC). The inner 13mm terminal near block is for ground and the outer one has two wires, 1 for battery and 1 for alternator.

Hope that helps.