• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Electrical Oooops.....

Ken F

IBA #44567
I recently rebuilt the transmission in my R1100RSL. After putting it all back together, trans works great, but I have no turn signals, hazards, no power to the powerlet outlets.
Everything else seems to work fine.
I'm assuming it is a grounding issue, but I cannot find anything showing the various points where the wiring harness grounds to the frame.
(anyone have anything on this?)

I'm really open to suggestions here.....I had the rear end up in the air of course, when the tranny was out. Could possibly be something where the
harness goes into the fuse/electrical box as there was quite a lot of tension on it while in the air.

Thanks,
Ken
 
FYI - Only wires should carry current - both ways. The frame should not. BMW is pretty good about this - at least in later years. They do use brown though as a "ground wire.
 
oops

Ken is it possible that one wire was not re-connected to the ground terminal on the battery? If not you might try a wire from the ground terminal to any of the ground connections on one of the non-working lights. If that completes the circuit you might assume that the open is between the battery and the light.
Lee
 
My manual shows that fuse #3 supplies the loads you mentioned + the RID.
Do you have power there?

Battery (-)ve is grounded under the battery tray.
 
Thanks for the replys. Yes, the RID works fine.
I will have to pull the tupperware & tank I guess and go through everything. Lee, I thought about doing that this afternoon, but I need to pull the swingarm again anyway to replace the rear seal on the trans - I thought I could slide it on without damaging it!! We all know how that worked out.
While I'm in there I'll check the grounds under the battery tray and the ones to the battery. It's got to be something pretty simple as everything worked before I pulled the trans.

NRPeterson, yes I'm aware of that but thanks for pointing it out though. Why are there several points where there are ground wires to the frame however? backup?

Thanks again!
Ken
 
Thanks for the replys. Yes, the RID works fine.
I will have to pull the tupperware & tank I guess and go through everything. Lee, I thought about doing that this afternoon, but I need to pull the swingarm again anyway to replace the rear seal on the trans - I thought I could slide it on without damaging it!! We all know how that worked out.
While I'm in there I'll check the grounds under the battery tray and the ones to the battery. It's got to be something pretty simple as everything worked before I pulled the trans.

NRPeterson, yes I'm aware of that but thanks for pointing it out though. Why are there several points where there are ground wires to the frame however? backup?

Thanks again!
Ken

The early /5 twins all the way until the present day use the brown wire for ground return. Usually it is attached to the frame at only one point. On the /5 bikes (1970) the brown wires were all terminated in one ring connector near the coils and grounded to the frame.
You may have a break in a ground wire, but unless someone is using the frame for ground with aftermarket wiring, it's not an unconnected wire to the frame. Do you have headlights, etc? Just wondering about the shed load relay return wire to the starter.
 
Chuck, yes headlights work fine-good thought on the load-shed relay.
It's only the turn signals, flashers & poweroutlets which do not work.
You know, I didn't check the horn......I'll do that today.

Ken
 
FYI - Only wires should carry current - both ways. The frame should not. BMW is pretty good about this - at least in later years. They do use brown though as a "ground wire.

Somebody forgot to tell BMW's engineers this. Maybe electrons are different in Germany. Many BMW models have battery ground to the transmission case and almost all circuits grounded on the frame backbone: Airheads, classik K bikes, F650, to name just the ones we own that have it done this way.
 
Instead of guessing if you have a ground side problem or a hot side problem, I would use a ohmmeter on the brown wire of one of the lights that is not working and see if there is continuity to the battery negative terminal. Do this with the ignition switch off. If you do have continuity then you do not have a ground side problem.
 
........... Do this with the ignition switch off. If you do have continuity then you do not have a ground side problem.

Well, not aalways. Your meter is only asking the circuit to carry a few milliamps, most loads are more. I remember a fully certified and career mechanic that worked for me once, that assumed the same, he spent an hour + trying to find an issue, his DVM said everything was good. He called me over after pulling his hair out, and we quickly determined the "ground" did have continuity, but would not handle a load, I don't remember whether it was loose, a poor crimp, or dirty connection, or feeding back through some other load.
 
After 35 years of electrical trouble shooting as my career, I would still use an ohmmeter to check for continuity. I would expect to have a near zero reading. I don't know how your mechanic friend checked or what kind of instrument he used for checking. I have seen other types of technicians (e.g. air compressor mechanic, HVAC)come in to were I worked and used other types of instruments to check for voltage and continuity. Some only give a light to indicate the reading. I have never trusted them for doing a REAL continuity check or voltage check.
 
There are other ways to determine if you have a hot or ground side problem.

1. Put one lead of a voltmeter on the hot side of the light that should be on and the other voltmeter lead on the battery negative. If you have battery voltage (12v) then your ground is bad. If you have 0V then you have a hot side problem.
2. Put one lead of a voltmeter on the ground side of the light that should be on and the other voltmeter lead on the battery negative. If you have battery voltage (12v) then your ground is bad.
 
There are other ways to determine if you have a hot or ground side problem.

1. Put one lead of a voltmeter on the hot side of the light that should be on and the other voltmeter lead on the battery negative. If you have battery voltage (12v) then your ground is bad. If you have 0V then you have a hot side problem.
2. Put one lead of a voltmeter on the ground side of the light that should be on and the other voltmeter lead on the battery negative. If you have battery voltage (12v) then your ground is bad.

NOW your cooking with gas!!!
 
Back
Top