I try not to wash my bike (with soap and water) more than once a year. I usually just use detail spray after rides. Well, I washed it last night and dried it my usual way, with a leaf blower, and today I noticed the brake light was always lit up.

I traced it to the rear switch by unhooking it and the problem went away. Hooked it back up and the problem reappeared. I pulled the switch out and sprayed a bunch of WD40 into it to try to lube it and displace any water that may have gotten in there. It didn't work.

I really don't see any other way of lubing / cleaning the switch. Any other suggestions?

I see used switches online for $15...might go that route. I'm having trouble finding a new switch in the online parts diagrams so have no idea what a new one would cost.

So I guess I'm asking if there is anything else anyone would suggest to get the brake switch working again? Anyone have an idea what a new one would cost?

It seems very strange to me that the brake light switch would fail closed due to water. It's just a set of contacts and even if it were completely flooded with water the switch would still work. Is it possible that it was broken before you washed and you just noticed it?

It's likely the switch could be taken apart and cleaned but don't think that would help as a dirty switch would generally fail open. Does the plunger still move freely in the switch?

Honestly I say just get a used on one eBay. They are cheap enough that it's probably not worth fixing.

yeah, could be a coincidence..but the brake light was definitely operating correctly before this. I check brake light plus turn signals and headlights before every ride. Last time I rode was a day or 2 before and it was definitely working before the ride...could have failed during the ride, though, who knows.

I'll probably just buy the ebay special, used switch.

Kind of a PITA to get the switch unplugged..pull some tail plastics and it's still a tight squeeze between frame parts to get to the switch to plug/unplug it. It's a couple inches in front of the flasher relay in case anybody needs to find it.

thought I'd circle back on this one...while waiting for my ebay part to arrive I thought I'd give my old switch another try. I'd soaked it with Corrosion X (an excellent penetrant / lubricant) a few days ago and turned it upside down so the lube would soak in better...I've been out of town since Monday..

plugged the switch back in and guess what?...worked fine. So now I'll have a spare, $15 rear brake switch sitting on the shelf..just in case.

I'm including a pic of the switch and the location where it plugs in...in case anyone was wondering.

Attached Images

File Type: jpg	brake light switch .jpg (250.0 KB, 5 views)
File Type: jpg	brake light plug in.jpg (331.1 KB, 4 views)