Unloader Relay Issues

[jlevie]

K5 & K7 (in the fuse box) are the unloader relays. The starter solenoid (on cars built after 8/87) grounds the coils when the starter isn't engaged to close the relays.

[Ipaman]

I have to bump this thread since I found it and it solved my windows and ac problem. I moved my black and green wire on my starter to the bottom post with the other small wire and everything worked perfect! I love this place:)

[sgtskid]

Bump for another car fixed! Instead of wrestling with the starter again only to argue with autozone that it wasn't a good starter. I wired the unloader wire to one of the studs on the housing of the starter. Everything works like a charm!

[Matt-B]

bump because im about to do this again, good info for people

[Karl]

windows and fan inop, except with front door open

Thanks for this thread. Fixed an intermittent problem a few years back. If I hit a bump or turned the fan and windows quit working. One day I discovered when the fan was out that the windows also worked when the front door was open - which it also does normally without ignition on. Finally I had enough keywords to find this forum thread.

Problem turned out to be a nut loose on the starter where the unloaders get their ground.

[IronJoe]

Sorry to bump an old thread but this appears to be right around the issues I am having.

Background: I have a 5/87 build date S14 swapped into a 3/89 build date 325i cabriolet.


Issue: I have intermittent blower motor & window operation similar to what others posted in this thread. I have swapped unloader relays with no success.


I see lots of later motors swapped into earlier cars, but not usually the other way around. As far as I can tell, I have the old style 3-post starter based on the build date (5/87) of my departed henna M3. The donor chassis is a 3/89 build date.

I'm wondering if this could be my problem? Does the chassis expect four wires, and the starter solenoid only has 3 connections? Any help here would be fantastic. Thanks!

[Karl]

Issue: I have intermittent blower motor & window operation similar to what others posted in this thread. I have swapped unloader relays with no success.

I'm wondering if this could be my problem? Does the chassis expect four wires, and the starter solenoid only has 3 connections? Any help here would be fantastic. Thanks!

Hi, Dave's post on p1 explains the problem but the challenging thing to get is the fact that the unloader relay coil has both ends connected to what normally seems would be positive volts - e.g. a + input on the starter relay coil I think. I may be wrong about which because mine was on the right post, just was loose.

Key on powers one side (I think 86) on the unloader coil so then all it needs is a ground on I think 85 to energize. That ground connects to a place on the starter that would get + voltage applied when cranking, but when not cranking is still connected through the windings to ground.

Your later harness/chassis I think should have that wire near the starter - I would first find it - disconnect it and measure/verify it connects to that pin 85 or wherever the unloader needs its ground. Once verified you could connect to a ground (maybe through a small inline fuse) - observer the relay works and windows work - then see if they are still intermittent - suggesting this route since you said intermittent and might need to subdivide the problem to figure out which side has an intermittent fault.