Brake light always on - 1979 GS850

[Steve]

Yes... it is brighter. I should also mention:

1. When I touched the hot wire to the ground (black) wire, the same thing was happening as test #2 (only the tag light came on at the same brightness)

2. You mentioned the light should be an 1157, but what was in there before, and what I have in there now is a 1034. Would that make any difference here?

3. The tail light filament never came on any of the tests

I'll remove the housing. Thanks!!

OK, more questions:
1. When you touched the hot to the black wire, where was your ground wire?
That black wire is for GROUND ONLY, the hot wire should never touch it.

2. A 1034 is OK, they are sometimes harder to find. Either one will work.

3. And yet, it did in a previous test.


Your license light (the lower one) should have a single-filament bulb, probably a 67 or an 89. It should only be ONE brightness, because it only has a single filament.

In one of your previous posts, you show both filaments ON, apparently while following a request to ground the black wire and power the brown wire. Your next test, powering the white wire, changed the brightness in the wrong bulb. I have a sneaking suspicion that somebody has crossed up some wiring or swapped sockets for the lights. How that might have happened, I don't know, but "previous owners" can be really crafty people.

I will repeat a previous request: remove the whole assembly from the bike so you can track where the wiring goes.

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Not only is it on, it looks like it's BRIGHTER!

You obviously have some problems with the wiring in the tail light. Remove it from the bike so you can see where all the wires go.

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Yes... it is brighter. I should also mention:

1. When I touched the hot wire to the ground (black) wire, the same thing was happening as test #2 (only the tag light came on at the same brightness)

2. You mentioned the light should be an 1157, but what was in there before, and what I have in there now is a 1034. Would that make any difference here?

3. The tail light filament never came on any of the tests

I'll remove the housing. Thanks!!

[Steve]

Test #2: Only the license plate light came on when I powered the White (brake) light



Interestingly, you mentioned the license plate light should go off when I touch the white one, but it's staying on... not sure if that means anything or not, but that's where I'm at! ...

Not only is it on, it looks like it's BRIGHTER!

You obviously have some problems with the wiring in the tail light. Remove it from the bike so you can see where all the wires go.

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Just pull that connector apart and do the testing in my post #17.

Testing in a systematic way will eliminate variables as you go. The test I described will tell you whether the lights themselves are working.

Once we see the results of those tests, we will move on to the next one.

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OK, gave the test a shot (thanks for the clear instructions!).

Test #1: Both lights came on a low/dim level when I powered the Brown (tail) wire



Test #2: Only the license plate light came on when I powered the White (brake) light



Hopefully you can see the proof of my method on the ride side (first is touching the brown wire, second is touching the white).

I just replaced the brake/tail light bulb today (to make sure it wasn't just a dead light) so I'm thinking that's not the issue.

Interestingly, you mentioned the license plate light should go off when I touch the white one, but it's staying on... not sure if that means anything or not, but that's where I'm at!

Thanks again Steve! Not sure what this means now though...

Thanks Steve!!

Yes, got all the parts (including the small plastic piece with copper and spring).

I'll give your test a try and post the results.

Thanks again, really appreciate it!

[Steve]

..., the "plate" I was referring to was the front brake switch plate.

OK, now it makes sense. Do you have all the other little parts that go to the switch? There should be a little square black plastic piece, a spring and a piece of U-shaped copper. If you don't have ALL of them, the switch will not work properly. The good news is that you can get replacement switches for less than $10.

This is what started this whole issue... I was fixing my front MC and the wires on this broke off. I soldered them back on, but now I have this other issue... no brake light.

No problem. As previously mentioned, make sure you have all the parts or buy a new switch, if needed.

Yes, thank you! I am such an amateur at all of this I don't even know how to do proper tests or where to start. So, I really appreciate all of your help!!

Believe it or not, that's why we are here.

I'll try this out. I think my connector is outside of the hosing box (see picture below) but I'll see if I can get any light that way and see what happens.

Yep, that's the connector right there, hanging with the other wires.

Just pull that connector apart and do the testing in my post #17.

Testing in a systematic way will eliminate variables as you go. The test I described will tell you whether the lights themselves are working.

Once we see the results of those tests, we will move on to the next one.

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What "plate"?

There is no "plate" in relation to brake light wires.

There is a wire that branches and feeds both, the front and rear brake light switches. There is another wire that comes from both switches (and joins together), then feeds the brake light. There is no "plate" anywhere.

Hi Steve,

Sorry, should have included pictures as I figured my description would be confusing... Anyway, the "plate" I was referring to was the front brake switch plate.



This is what started this whole issue... I was fixing my front MC and the wires on this broke off. I soldered them back on, but now I have this other issue... no brake light.

I think it has been hinted at here in this thread (I have helped in a couple other wirng threads recently, so am not sure if it was this one), but I am going to come right out and plainly ask you to do some testing, not guessing.

Yes, thank you! I am such an amateur at all of this I don't even know how to do proper tests or where to start. So, I really appreciate all of your help!!

Look in front of the brake light housing. That would be under the "glove box" inside the tail fairing, behind the seat. You should see a flat, three-pin white plastic connector that feeds your tail light assembly. Note that there are three wires there, a black with white stripe (ground wire), brown (tail) and white (brake). Separate the connector. Use a piece of wire about two feet long (you do have some spare wire sitting around, don't you? If not, go get some), strip a bit of insulation off each end. Insert one end into the connector that is attached to the tail light, connect the other to a good ground (chassis, battery, whatever). Take another piece of wire about the same length, strip some insulation from both ends. Connect one end to a power source (fuse box, battery, whatever). Be careful that the other end does not touch any metal, or there WILL be fireworks. Touch the loose end to the brown wire in the tail light connector. You should see both bulbs light up, and be about equally bright. Now remove the wire from the brown wire and touch it to the white one, the brake light should come on brightly, the license light will not be on. If those simple tests do not work as described, you have problems with your tail light housing, the socket or the bulb.

I'll try this out. I think my connector is outside of the hosing box (see picture below) but I'll see if I can get any light that way and see what happens. Again, thanks for your tips!!

[Steve]

I've also reconnected the front brake light wires to the plate. Still, no luck on the brake light turning on.

What "plate"?

There is no "plate" in relation to brake light wires.

There is a wire that branches and feeds both, the front and rear brake light switches. There is another wire that comes from both switches (and joins together), then feeds the brake light. There is no "plate" anywhere.

I think it has been hinted at here in this thread (I have helped in a couple other wirng threads recently, so am not sure if it was this one), but I am going to come right out and plainly ask you to do some testing, not guessing.

Look in front of the brake light housing. That would be under the "glove box" inside the tail fairing, behind the seat. You should see a flat, three-pin white plastic connector that feeds your tail light assembly. Note that there are three wires there, a black with white stripe (ground wire), brown (tail) and white (brake). Separate the connector. Use a piece of wire about two feet long (you do have some spare wire sitting around, don't you? If not, go get some), strip a bit of insulation off each end. Insert one end into the connector that is attached to the tail light, connect the other to a good ground (chassis, battery, whatever). Take another piece of wire about the same length, strip some insulation from both ends. Connect one end to a power source (fuse box, battery, whatever). Be careful that the other end does not touch any metal, or there WILL be fireworks. Touch the loose end to the brown wire in the tail light connector. You should see both bulbs light up, and be about equally bright. Now remove the wire from the brown wire and touch it to the white one, the brake light should come on brightly, the license light will not be on. If those simple tests do not work as described, you have problems with your tail light housing, the socket or the bulb.

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Brake light not working

Question now though is, what happens if I connect the wires (rear) and leave the front as they are, and the brake light is still not coming on? Do the front wires NEED to be connected to the plate in order for the brake light to work properly?

I've reconnected the rear brake light wires but the brake light is still not coming on. I've also reconnected the front brake light wires to the plate. Still, no luck on the brake light turning on.

So, I am thinking I have a bigger problem... Or, could it be the fuse?

As a side note, I haven't had any rear turn signals on the bike, but I did have them laying around. I was able to put them on before this issue and they would turn on. Now, however, I plug them in and not able to get any light from them either...

What Redman and Steve said! terrylee

[Redman]

So you're saying the brake light bulb is dead... it's really that simple and I've missed it this whole time??

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No. Not what anybody is saying.
You have the brake switch wiring apart, so brake light should not be on, and it is not.


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Brake light and tail light on though both front and back are disconnected

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Ah, like others have said.
THat is not the brake light AND the tail light.

The upper bulb is the tail / brake light and has only one filimant lit up, not both filiments. One filiment is tail light, other filiment in same bulb is the brake light.

The lower bulb is the licence plate light (sometimes called tag light).

So, now reconnect the front and rear brake light switch and see that is still only one filiment in the upper bulb on. THen try each brake and see that the brake light comes on in addition to the tail light.

[Steve]

If so... any recommendations on where to get a replacement bulb? I checked out PartsShark and I am not seeing anything on the OEM parts fiche.

Just go to your favorite auto parts store and get an 1157 bulb.

Also, this is going to sound really amateur, but to replace the bulb, can I simply pull it out, or do I need to un-hook it somewhere?

Standard procedure is to push in (about 1/16"), twist to the left (about 30 degrees), then pull it out. If there is a lot of corrosion between the bulb base and the socket, it will be difficult, be careful that you don't break the glass and cut yourself. If you do break the glass, you can then use needle-nose pliers to grab the base to twist and pull.

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Large bulb has only one filament lit, which should be tailight, other filament should light up with brakes. Smaller bulb is for lic. plate. terrylee

So you're saying the brake light bulb is dead... it's really that simple and I've missed it this whole time??

If so... any recommendations on where to get a replacement bulb? I checked out PartsShark and I am not seeing anything on the OEM parts fiche.

http://www.partshark.com/fiche_selec...141&x=138&y=33

Also, this is going to sound really amateur, but to replace the bulb, can I simply pull it out, or do I need to un-hook it somewhere? Reason I ask is that I've tried to pull on it to inspect it, but it doesn't come out very easily and I'm nervous to pull too hard and cause any more problems.

Thanks for your help!!

Large bulb has only one filament lit, which should be tailight, other filament should light up with brakes. Smaller bulb is for lic. plate. terrylee

[cowboyup3371]

Unwrap your harness and make sure you don't have any bare wires touching someplace else. Your taillight and the main brake light wire runs through the harness from front to back. The rear just plugs into it.