85 fj1100 rear running light doesnt work

[iridewheelies]

The other day i noticed that when my bike is running that the rear running light does not work. The rear brake light works only when i apply rear brake. So the brake light works, but the running light does not, making the bike unsafe to ride at night and in general. People here in omaha are the worst drivers. Not sure what the fix is. I switched the bulbs around to see if one of them was bad, but they both worked when applying rear brake. Could it have something to do with the light sensor attached to the rear brake lever? I had the rearsets off because I powder coated them. Maybe i didnt put the sensor thing back together correctly? Let me know what you guys think. Thanks! Can also powder coat parts for yall if u pay shipping!

[red]

The other day i noticed that when my bike is running that the rear running light does not work. The rear brake light works only when i apply rear brake. So the brake light works, but the running light does not, making the bike unsafe to ride at night and in general. I had the rearsets off because I powder coated them. Maybe i didnt put the sensor thing back together correctly? Let me know what you guys think.

Iride,

Tail light bulbs have two filaments inside, one is the brake light, one is the tail light.  Remove the bulb from the bike.  Clip the bulb base to ground (you can use a big clamp for this, like a jumper cable).  Touch 12Vdc with a wire to each of the two small contacts on the back of the bulb.  One contact will light the bulb (the tail light), and the other contact will light the bulb brighter (the brake light).  Chances are the tail light part is burned out, and you just need a new bulb.  A good brake light does not mean the taillight part will work, only that it should.  There is no sensor that matters, for the taillight.  If both parts of the bulb work, and if you removed the light fixture from the bike earlier, maybe you did not re-connect both of the rear wires for the lights (tail-light wire and brake-light wire).  There should be two color-coded wires to the taillight fixture, and probably a black ground wire as well.

[Pat Conlon]

No, it has nothing to do with the stop switch, that works the brake light fine.

There are 2 power wires to the rear light bulbs (and a black ground)  The first power wire is 12v energized when you turn the key on (running light) and the second power wire energizes the 2 second filliment in the bulb when you apply the brake.

It's this first power wire for your running lights you want to trace.

If you have a Owners Handbook for your specific model FJ, in the back is a color coded wiring diagram you need to trace the wires. If you don't have an Owners Handbook, see my signature line...it's free to download.

Let us know what you find.

Pat

[TexasDave]

On the 84 and 85 FJ's the three wires running to the tail light are Yellow(Brake), Blue(Tail Light) and black(ground). With the key on see if the blue wire has 12 volts to it. If not you are going to have to track down where the bad connection is.

Dave

[iridewheelies]

Ah i see. These bulbs say japan on them they have to be original. Lmfao. So i pulled out my multimeter one side read 3.5ish ohms and the other side of the bulb read no ohms. Goin to wally world to get some bulbs. I feel dumb now thanks guys

[Pat Conlon]

With the brake on, you've confirmed that you have 12v power at both terminals in the plug(s)?

It's rare that both bulbs burned the the running light filaments at the same time...unless you already had one bulb already out and you didn't notice until the second bulb burned.

I applaud Yamaha for designing a tail light with redundancy.

[Motofun]

Wally world and auto store bulbs (of the proper type) will work but they don't seem to last as long.  I've noticed that the Yamaha bulbs have a central post that helps stabilize the filament and prevent vibration from breaking the filament prematurely.  I have yamaha bulbs that last 10 to 15 years and auto store bulbs that don't make it a year. 

[red]

Iride,

You can also install a superbright LED taillight/brakelight of the correct type, and it may never burn out again.  You MUST use a rel LED bulb inside a red lens like the tail light housing, because white or other colors of LEDs would look very dim in there, otherwise.  LEDs can make good tail lights and brake lights.

Do not use LED bulbs in the turn signals, because it would affect the flasher unit unless you do other stuff besides replacing the turn signal bulbs.

[ribbert]

Do not use LED bulbs in the turn signals, because it would affect the flasher unit unless you do other stuff besides replacing the turn signal bulbs.

or use resistor bulbs.