Brake light issue!

[Striker]

Hello to everyone again. I after a little bit of rain here in phoenix (yes it does happen) I noticed that when I got home and did an inspection the brake light seems to be stuck on. Looked through all the fuses and wiring connections I could find to see if there was any water and found nothing. All was dry. Disconnected the front brake sensor and still stayed on. Rear seems to still move freely but am curious if there is something that could be causing it to be in a stuck position. This is an immediate concern of mine as I would like other people to know when I am stopping Any advice on what to look for and where is much appreciated thank you!!

[FJmonkey]

Is the key turned too far? One click the right too many and the tail light comes on.

[WestOzFJ]

The micro switch in the front m/cyl and the rear m/c plunger switch are switching positive.

With the front and rear switches both disconnected from the wiring does your stop lamp still illuminate?

If so then does it stay illuminated if you turn the park/tail lamp off?

If it still stays on with the tail/park lamp turned off then it's possible the 12v feed wire to either switch is bridging/shorting over to the yellow wire before the power even gets to the switch.

If the the stop globes go out with the tail off then the stop wire is picking up a 12v+ feed from the tail wire - maybe rubbed through and/or crushed together.

If you had a short to ground you'd be blowing fuses, so your looking at finding where that yellow wire is getting power into it.

If none of the above works, start pulling fuses to give you clues as to which circuit is the illicit power feeding culprit will also help you narrow down where to look.

There are 3 wires go to the tail (on my 87at least):
blue is tail lamp power,
black is 0 (or minus or ground or whatever you prefer), and
yellow is stop which is switched 12v+

I've got a wiring harness layed out in the garage of a buck naked '86 so if it helps you to know more about what leads where I can have a closer look at it and pass on whatever info....

[Firehawk068]

Hello to everyone again. I after a little bit of rain here in phoenix (yes it does happen) I noticed that when I got home and did an inspection the brake light seems to be stuck on. Looked through all the fuses and wiring connections I could find to see if there was any water and found nothing. All was dry. Disconnected the front brake sensor and still stayed on. Rear seems to still move freely but am curious if there is something that could be causing it to be in a stuck position. This is an immediate concern of mine as I would like other people to know when I am stopping Any advice on what to look for and where is much appreciated thank you!!

I would probably check your rear brake light switch adjustment........Since i have owned my '90, I have found it to be finicky at best.......Out just a little too far, and the brake light stays on......in just a bit too far, and it doesn't activate the light.....On mine it seems a very small window of adjustment to where it works properly....Could have got some water in it also, and gummed up to where it is stuck.....(mine has gotten stuck before to where the weak spring doesn't pull it anymore)

If you need assistance, I'm in Mesa. PM me, and I'll give you my Phone number, and address, and you can drop by this weekend..
I'm free pretty much all weekend (except for tomorrow morning for a few hours. We're taking the kiddies to Boo-at-the-Zoo)

[andyb]

Yup, unplug the switches and see what happens, can isolate it to either of them or not.  Pretty easy circuit to troubleshoot.

[Striker]

Hey thanks for the advice. I'll be trying all that out later today. Let you know What I find out. One thing I tried to pull off the connection to the rear switch to see if that was the culprit but seems a little hard to disconnect. And I don't want to break anything so just making sure what the best way to disconnect the rear switch. Thanks

[Firehawk068]

As far as I know, you can't disconnect the wires down at the switch.......The wires are made right into the back of the switch......They should disconnect further up the subframe near the master cylinder reservoir somewhere.
Just follow the wires up there.....Should be a couple of "bullet" plugs.

[Striker]

Alright I have disconnected both the front and rear brake sensors and no change. Light also has both globes lit when key is turned past steering lock to park. I'm trying to follow the wires to see where it could be bridging or shorting out. But looks like it goes to a central wire harness just behind the battery up to the front of the triple trees.

[rktmanfj]

Alright I have disconnected both the front and rear brake sensors and no change. Light also has both globes lit when key is turned past steering lock to park. I'm trying to follow the wires to see where it could be bridging or shorting out. But looks like it goes to a central wire harness just behind the battery up to the front of the triple trees.

There's nothing wrong with it... the park function is supposed to work that way, IIRC

Randy T
Indy

[Striker]

The problem is that the brake light stays fully lit when bike is turned on. When turned to running with both sensors disconnected the brake light still is full on.

[Arnie]

The problem is that the brake light stays fully lit when bike is turned on. When turned to running with both sensors disconnected the brake light still is full on.

For that to happen you have to have a connection (short) to the yellow wire of +12V somewhere after the brake switches. 
Are you sure that its not the taillight illuminated?  That could be a problem in the main switch or the blue wire which illuminates the taillight could have a short to +12V.

With the brake switches connected, and the ignition ON, does the light get brighter when you step on the brake pedal?  If so, then the problem is in the tail light not the brake circuit.

HTH,
Arnie

[Striker]

I tried with the switches connected and the ignition on and the light does not get any brighter when I hit either brake.

[racerrad8]

...light does not get any brighter when I hit either brake.

Make sure the bulb is installed correctly. If it is forced in 180* out, the brake light circuit will be the only one working.

The tabs on the side of the bulb are offset and are designed to only be install one way...with that said there have been millions installed 180* out and the brake light is on when the taillight should be working.

Heck you might even make sure it is an 1157 bulb as well...

Randy - RPM

[Firehawk068]

He said he has this issue after riding it in the rain.........I'm assuming it worked fine before it got wet.....
Would probably have to check through the wiring scematic to follow the trail of power through the harness to see where it is shorted out.........
I've got diagrams if you want to bring it by some evening......I get home from work around 6:30

[Yamifj1200]

Make sure your ground wires are in good condition and any connections to the frame is clean and not rusted. Also look at the wiring connections take make sure they are clean and not corroded.

  Eric M