My brake light only lights with front brake. is the brake light switch bad?

 

I've got the same issue. Probably the pressure switch for the rear brake. Follow your rear brake line back and you'll run into it. I haven't trouble shot mine yet, but that has to be the problem.

 

Same here, I got a factory switch in the basement waiting for the snow to kill the 2012 riding season, mine I gotta take off the exhaust to make it fairly easy.
Sneak your onto the switch and inspect that in fact both cables are on the spade connectors, which is on the actual switch. If they're there then take them both off and stick a jumper, a paper clip, anything to connect to the two wires together and you SHOULD see the lights brighten, ie the brake light came on. If the light is not coming on the re is a break in the brake wiring which is highly unlikely. If and when the light come on spend the money at the dealership because the switches at auto zone are zinc and will rust because they are exposed to water when riding in inclement weather.

 

You lose brake fluid when you pull that switch?

 

You will lose fluid and have to bleed your rear brake when you change it out.

 

Have the same problem and actually stumbled upon half-assed temporary fix. If you're currently running a conventional bulb in your brake light throw in a cheap LED and you may be getting enough amps to it to light it up. Turns out when I replaced my cracked tail light assembly it came with a cheapo LCD bulb. Shockingly the damn thing works now.

 

Determined that my rear brake light pressure switch is bad. Question is, how the hell do you get it out of there? There's like no clearance and I can't even get a wrench on it... I can see it, but it's nestled so tight against the frame.... maybe a shaved down deep socket...

 

Crow feet wrench head maybe? But a pair of water pump pliers may do, a basin wrench if you're bike is on a lift. I gotta take my exhaust off to make it less painful. Some hero will say they did it without removal but they are a contortionist.
Bleeding brakes? Flame suit on>>>>
Fill a Dixie with brake fluid and drop switch inside, notice air bubbles escape, remove connectors, stop get up and limber up then crack knuckles, remove brake switch drop on floor take new switch and screw it in. Reconnect everything then take it down the block and see squishiness or sponginess of pedal. If you notice no difference, realize that this is your life, then you're done. If pedal is not satisfactory then you gotta bleed brakes.
We're not talking about much fluid loss but maybe an ml or two...
Bon chance!

 

Guess I was lucky. Mine was a snap to change and the amount of break line fluid that actually comes out is so minimal that I didn't even bother with bleeding my rear break. It was literally like two drops of fluid. I just just had the new switch ready with some thread sealer on the threads to pop in one I got the stuck one out. Just a thought, have you considered cutting some of zip ties that hold your break line to the frame to see if you can pull it away from the frame to give you enough clearance?

 

Get out a volt meter and start testing wires. Check at the brake switch when you apply pressure again at the like when applied. I had to to this on cars for the brake kill on remote starts. Many car had bad brake switches. It could be the a ground wire for the switch, bad switch, or the wires just came lose. I don't have much experience with bikes but the idea is the same. Hope this helps with all the other comments from the rest of the group.