Brake Lights started flickering and now stuck constant on

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JasonB

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Need a bit of help trouble shooting my electrical issue. Bike 2007

Last ride my brake lights started flickering on and off. (Tail light remained on and constant). I stopped for gas and fiddled with the the brake switches, and now the brake lights have stopped flickering but remain constant on and will not go off. First thought was brake switch(s) not disengaging or return to normally closed.

Back home:
I have checked the rear break switch and the front break switch and all looks to be in order (continuity test). Next I tried to verify the brake relay is engaging, I can hear the relay engage (click) and disengage with both the front and rear brake switch action. So the brake relay seems good. Next I tried tracing out continuity/voltage on the bulb sockets, that is when I accidently shorted out the tail/turn signal fuse. So no tail lights or turn signals now. This is where I ran out of time, so did not verify which fuses are actually blown yet. Where is the hazard/tail light fuse, are they under the "A" panel by the battery or down by the air filter?

Interesting part, the brake lights started working after shorting out the tail lights. Front and Rear brake switches now work to light both filaments of the tail light bulbs (brake and tail) and when released the both filaments go out. Also if the brake is engaged not only do I have brake lights come on, but if I engage the turn signals or hazards they work as well. (Thinking this also confirms brake relay is working!)

This leads me to think that the brake switches are both good and so is the brake relay. I suspect the 12Vs from the tail light (or turn signals?) circuit is somehow being shorted into the positive line to the break bulb filaments some where between the bulb sockets and the brake relay causing the break lights to always be on with ignition.

Any suggestion on where to start looking for the short? Is it in the hot tail light wire (blue?) crossing to the (yellow?) break light wire. Presume it is hot to hot short. Or is this a ground issue in a plug somewhere perhaps. Also open to thoughts on what I have tested above and differences of opinion in ruling out switching/relay as being good.

Also I bought the bike new in 07 and stock wiring is not modified. One exception perhaps, I had the dealer do the wire harness ground recall fix years ago.

Thanks,

Jason
2007 FJR in Indiana
 

RossKean

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Lots of possibilities. Switches are most likely. Of course. Make sure the rear brake pedal isn't sticking.

Something that has happened to me (not on an FJR) - make sure there is no corrosion in any of the light sockets. That can do some strange stuff.

I assume that you don't have spider issues? Look for odd signal light behavior (both on) or a high beam indicator when high beam isn't on.
 

Ridelikethewind

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Check your actual bulb contacts, I have seen a few bulbs where the lead part of the bulb contacts get so flat that they touch the tail light side of the brake light bulb contact and turn it all on. Keep us posted what you find.
 

JasonB

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Thanks for the suggestions - I'll recheck the rear brake switch and the bulbs for double contact. Then try to trace out from the sockets back looking for a short.
 

torch

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that is when I accidently shorted out the tail/turn signal fuse. So no tail lights or turn signals now. This is where I ran out of time, so did not verify which fuses are actually blown yet. Where is the hazard/tail light fuse, are they under the "A" panel by the battery or down by the air filter?
[/QUOTE]
Behind the battery. There's two fuseboxes there, I believe it is the right hand one, but could be wrong about which one.

Interesting part, the brake lights started working after shorting out the tail lights. Front and Rear brake switches now work to light both filaments of the tail light bulbs (brake and tail) and when released the both filaments go out.
That sounds like a grounding issue. A bad ground forces power to seek an alternative path. Since the brake, tail and turn filaments all share a ground wire at the rear, the brake may be seeking ground by back-feeding through the tail and/or turn circuits to another ground point.

I would start by unplugging the rear lighting harness connector under the left hand side cover by the air box, remove all bulbs and test continuity through the harness and sockets.

On my 06, I found one wire had broken internally right at the socket. The insulation was intact so a visual inspection did not reveal the problem, but the conductor inside was broken and had no electrical continuity. I was able to solder a short wire to the rear of the connector and splice that into the harness.
 

RossKean

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That sounds like a grounding issue. A bad ground forces power to seek an alternative path. Since the brake, tail and turn filaments all share a ground wire at the rear, the brake may be seeking ground by back-feeding through the tail and/or turn circuits to another ground point.
I'm kind of thinking along the same lines - especially socket or bulbs. Corrosion, defective or messed up wiring. At least for Gen II, Yamaha was NOT generous with excess wire and it can be a bit of a challenge just to change a bulb - let alone messing with wires or sockets.
 

JasonB

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Solved! :) You gents were on top of it.

Turns out was a bulb shorting in the socket.

  1. Re-tested the brake switches and relay - good
  2. I pulled and tested both bulbs - both tested good.
  3. Checked and tested the sockets - both were clean, no corrosion and continuity check out. (I did the with fuse out, so no voltage-Grd verified).
  4. Puzzled not seeing a tail-brake short. Moved on to disconnect the tail harness near the filter box.
    1. Continuity good, no short in the tail harness
    2. Replaced the blown tail light fuse, voltage is correct with breaks applied and released coming to the tail harness. Hum! Re-plugged the tail harness back in.
  5. Back to re-check bulbs/sockets.
  6. Ignition on - the brake lights were off :), only lasted for a few seconds then came on :-( .
    1. I did nothing but re-assemble and insert the orig. bulbs.) Odd...
  7. Twist pull and insert each bulb again - issue remains. Grab a new pack of bulbs and rotate old/new found one of the old bulbs is shorting Tail - Brake circuits, this is causing brake light to stay on and the turn signals to work with the tail light fuse pulled.
    1. What is odd this only happens if two bulbs are pugged in, the bad bulb works if it is the only bulb installed so made it harder to find. (this still puzzles me, I suspect it is starting to fail, but not fully shorted yet. Will never know its in the trash now!)
Whish I had spent a bit more time when I first checked the bulbs/sockets, brushed over this as the old bulbs were actually fairly new, but not brand new - 12mo old/4k miles. Lesson learned.

Again thanks all for the pointers and location references. Kept me focused in the right area.

Jason
 

RossKean

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Solved! :) You gents were on top of it.

Turns out was a bulb shorting in the socket.

  1. Re-tested the brake switches and relay - good
  2. I pulled and tested both bulbs - both tested good.
  3. Checked and tested the sockets - both were clean, no corrosion and continuity check out. (I did the with fuse out, so no voltage-Grd verified).
  4. Puzzled not seeing a tail-brake short. Moved on to disconnect the tail harness near the filter box.
    1. Continuity good, no short in the tail harness
    2. Replaced the blown tail light fuse, voltage is correct with breaks applied and released coming to the tail harness. Hum! Re-plugged the tail harness back in.
  5. Back to re-check bulbs/sockets.
  6. Ignition on - the brake lights were off :), only lasted for a few seconds then came on :-( .
    1. I did nothing but re-assemble and insert the orig. bulbs.) Odd...
  7. Twist pull and insert each bulb again - issue remains. Grab a new pack of bulbs and rotate old/new found one of the old bulbs is shorting Tail - Brake circuits, this is causing brake light to stay on and the turn signals to work with the tail light fuse pulled.
    1. What is odd this only happens if two bulbs are pugged in, the bad bulb works if it is the only bulb installed so made it harder to find. (this still puzzles me, I suspect it is starting to fail, but not fully shorted yet. Will never know its in the trash now!)
Whish I had spent a bit more time when I first checked the bulbs/sockets, brushed over this as the old bulbs were actually fairly new, but not brand new - 12mo old/4k miles. Lesson learned.

Again thanks all for the pointers and location references. Kept me focused in the right area.

Jason
I assume that you are aware that the 1157 combined tail/signal bulb has a right way and a wrong way of inserting? The locator pins are not the same height on both sides. It is possible (not easy) to get them the wrong way around with only one of the pins locked in a slot and the other jammed between the bulb and socket. (The two filaments are different wattages which is why the pins are not symmetrical.) Also, if they are not fully twisted into the lock point, the two solder pads on the bottom may not make proper connection with the contact points in the socket. They could even short between the contacts. Any corrosion in these sockets will really mess stuff up.

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