[pjessen]

On a ride tonight, I stopped the bike to take some notes. When turning on the key, the lights come on, then a snap, and all lights go dark, no electrical power at all. Flicking the key on and off to all positions does nothing. After 3-5 minutes, I turn the key, and all lights come on, I start up and ride 35 miles home without incident. This is the second time its occured, a month and several rides/miles distant.

I assume I have an ignition key problem? Why the delay? Any help? Thanks.

99LTC, 42k, no accessories on at the time of failure (no radio or aux lights)

 

[dronning]

Sounds more like a main relay.

Breakers/relays usually reset after a short period of time. They can go bad or just become weak so they trip more easily. Do you have allot of extra lights wired in? The initial load when you turn the bike on might be pushing the limits if everything is on. 3-5 min reset seems long so you may have a wire running hot due to a bad connection or overload which could also trip a relay and cause the long reset (has to cool down).

I'm not familar enough with the LT to tell you where to look for the main relay but thats where I'd look first. When I get back home I'll check out the wiring diagram.

Dave

 

[mneblett]

Breakers/relays reset after a period of time. They can go bad or just become weak so they trip more easily. Do you have allot of extra lights wired in? The initial load when you turn the bike on might be pushing the limits if everything is on.

I'm not familar enough with the LT to tell you where to look for the main relay but thats where I'd look first. When I get back home I'll check out the wiring diagram.

Dave

Good thought -- the LT has what BMW calls a "Load Relief Relay" which turns off auxiliary loads such as lights when the starter is activated. The relay grounds through the starter. While this relay may be failing, the "snap" suggests something arcing. Before looking to the relay (which is in the electrical box under the tank), I'd suggest checking whether the wire from the relay which makes the relay's ground connection is loose at the starter. Randy Prade lost his lighting during a trip due to this. You can see the connection (with a flashlight) by raising the seat and looking under the frame backbone, on the rider's left.

 

[pjessen]

Thanks, Dave and Mark. I'll be stripping it down this afternoon. You verify the existance of a "master" relay, which is what it acts like. I'll go hunt. Thanks again.