BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

I thought I might have to examine the wiring harness for faults, because I couldn't solve the multiple electrical problems with the 2002 R1150R. After multiple recent modifications, the headlight would not work, nor would the turn signals light. The emergency blinkers and the heated grips were out. The horn did not work. The small parking light bulb in the headlight did not work, nor did the license plate light. There was no voltage to fuses 2, 4, and 7. Yet the bike would start and actually ran well. The brake lights came on normally. The clock worked.

There are about 28,000 miles on the bike and I am the second owner, putting on about 3500 miles. I have gone over the bike fairly extensively over the last several years, replacing and upgrading, and it recently has run very well.

The last round of modifications: Cyclops LED headlight and Weiser Technik LED rear turn signals, Throttlemesiter removal, Atlas throttle lock installation, Grip buddies, Barkbusters, Wunderlich handlebar risers, and Wunderlich footpeg lowering kits. All to make a trip from PA to the rally in Montana in June, which I won't do now due to COVID.

One last ride after all was installed, and I noted the headlight wasn't on when I pulled up to the garage. Then I found all the other electrical problems I outlined above.

Wiring, ignition switch, something I screwed up in moving or splicing the wiring? I found that very occasionally, things worked, but I could locate a reproducible cause. Pored over the Clymers electrical schematic, but it wasn't complete enough for me to diagnose the problem. I was bout to take off the tank and the rear, once again after doing the rear turn signals, to look at the wiring harness, after reading on here about the unfused headlight circuit.

Yesterday, I turned the ignition switch on, and as usual the fuel pump came on and the panel lights seemed normal, but all the other electrical faults were present, and no headlight. Again, started moving wires around in the front, trying to jiggle a loose connection or plug, and then all the faults cleared! The headlight came on and all the other systems worked. But when I switched the ignition off, then on again, the faults were still present. After some time, in frustration, I put the key in the ignition switch and turned it on. And did nothing else. Didn't touch anything. After a brief period, (20-30 seconds?), the headlight came on and all the electrical systems worked normally. Tried this again, and found that it did work, but not every time.

I remembered a forum's topic on the load relief relay and its function (the books don't spell out the electrical logic), so I opened the fuse box and began tapping on the relays. Headlight came on! But when I turned the ignition key off, then on, the same electrical faults remained. I remembered reading that a member had switched the load relief relay with the adjacent horn relay, so I did that. Everything then normalized and worked, with the exception that the horn only worked intermittently.

So today, I drove to Montgomeryville Cycle Center and picked up a new load relief relay (part # 61 36 6 902 041) and installed it. Everything works now. Every time.

So in part this is a tribute to the accumulated knowledge which people have published on this and other forums, and I am grateful for that.

John

Where is this load relief relay located? in the fuse box area under the seat? What's it look like too.
Thanks, I'll put it in my service folder..

The load relief relay is in the underseat fuse box. Can't load a picture easily here form my computer, so I apologize for the following:

There are three rows in the fuse box. The back row is for the fuses, and the front and middle rows are for the relays.

On the front row, left side there is a large relay - this is the starter motor relay. The smaller relay next to it, (moving toward the right side; second one in form the left) is the load relief relay. The third relay in from the left side is the horn relay, and is identical to the load relief relay.

Hope that helps.

Those small black relays in that row are all the same, and you can switch them around, might try that.
Looking forward the 1st relay (next to the bigger starter relay yellow I think is the load relief relay, its next to the horn relay.
Swap them and see what happens.

The replacement relay I bought is yellow instead of the original black. Same part number.

Hope that fixed your problem.
I have a couple of extras, both black and never had to use on in 16 years and a bunch of miles.

Perhaps this helps