Rear Light Wont Switch Off

[gringod]

I've got an 04 R1200GS.

A few weeks ago I had a rear light failure warning come up on the instruments. I pulled apart and cleaned all the switches and the rear light cluster, cleaning all the very dirty connections fitted a new bulb and ACF50ed everything.

Since then it's been working fine until two days ago. It's now decided that when I switch the bike off the rear light remains ON. What's really odd is that the light will randomly stay on for anything up to an hour, then switch off, then on again and so on... almost seems like a capacitor is charging and discharging.

Has anyone else had this problem and can help with a solution?

The only mention of a similar problem I've found is on this post, which mentioned needing a new instrument cluster but doesn't say if that fixed it: http://www.ukgser.com/forums/showthread.php?t=258486

 

[Poley]

I had similar problems, described here. Is it just the rear light that goes on, or is the front sidelight too? (I had similar symptoms, but I think my LH indicator malfunction was inadvertently operating the parking lights).

As my lights worked fine when dried out, I bought a switch from Farnells and cannibalised the rubber seal as a replacement, but left the original microswitch to avoid unnecessary soldering.

There's also a thread here with some pictures of the perished seals and a discussion on how they were dealt with.

 

[gringod]

It's just the rear light that stays on and I haven't had any problems with the indicators.

However, I'll pull the controls appart tomorrow just to makes sure.

Thanks.

 

[gringod]

Ok, I pulled apart the handle bar controls today and the rubber seals all seem fine. I also disconnected the instrument/clock panel and the rear light still stays on. I've got the battery disconnected at the moment so I'll be able to use the bike in the morning, I wonder if leaving it with no power might reset something in the computer.

If that doesn't work I think it might be time to take it to Mr BMW Dealer and get it hooked up to a computer.

 

[Pukmeister]

Have you tried using the steering lock to the opposite side than normal when turning off the ignition ? Does it occur in both left/right positions ??

My suspicion is that something is putting the bikes controllers into 'parking light' mode as you turn off the ignition switch, such as a chafed loom around the headstock, worn switches on the handlebars etc etc.

Also worth ensuring the bikes battery is fully charged, low voltages can sometimes throw up weird faults with the bikes electronics.

 

[gringod]

Well, it looks like the problem has magically sorted itself out! As I use the bike for getting to work I charged up the battery last Sunday and left it disconnected over night to make sure the bike would be running on Monday morning.

Since reconnecting the battery I haven't had any problems. I can only assume that leaving the battery disconnected overnight has completely reset the computer and cleared any fault that may have been causing the rear light to stay on.

 

[Deleted account 190920001]

or something has dried out?

 

[gringod]

It wasn't wet to start out with, so I don't think that was the problem.