Stupid question - brake light on cluster

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Wrenchmorethanride

XS650 Enthusiast
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Hi All

A friend of mine gave me his 79 xs650. It’s been sitting for decades. Trying to get her back on the road.

So far I rebuilt carbs, changed oil, adjusted valves and worked on brakes.

Brakes are where my question comes in.

When I turn the key to the on position the brake/tail light comes on. Is this normal? There’s another switch over on the right handlebar for engine run\stop. If I switch that to stop the brake/tail light goes off.

Is this normal or do I have an electrical issue to chase down?

I did replace the front brake cylinder and rebuilt the rear. Maybe I did something wrong?

Thanks for your help!
 
Hi, @Wrenchmorethanride, welcome to the forum. There's no such thing as a stupid question, but I'm not clear which light is coming on. Is it the brake light at the rear, or the red warning light on the cluster at the handlebar? From the thread title, I think you mean the latter?

This would be the rear lamp failure warning. It confussed me to when I first had my XS by coming on every time I switched on - turned out it came on because I had disconnected the rear lights. It's not a very useful feature, but Yamaha had a habit of fitting 'safety features' which IMHO are a bit unnecessary or even misguided. For example, the light checker which monitors the headlamp - if your dipped beam filament fails, it switches the main beam on. Now, that's gonna annoy oncoming traffic. So most people disable or remove the unit.

Check that the rear lamp works and that light should stay off. But don't hesitate to ask more questions. Cheers, Raymond
 
No it’s not normal, however check your rear brake light switch - it may be activated causing the brake light to com on. When you turn the kill switch to off it should come off as it cuts power to the bike
 
Raymond said:
Hi, @Wrenchmorethanride, welcome to the forum. There's no such thing as a stupid question, but I'm not clear which light is coming on. Is it the brake light at the rear, or the red warning light on the cluster at the handlebar? From the thread title, I think you mean the latter?

This would be the rear lamp failure warning. It confussed me to when I first had my XS by coming on every time I switched on - turned out it came on because I had disconnected the rear lights. It's not a very useful feature, but Yamaha had a habit of fitting 'safety features' which IMHO are a bit unnecessary or even misguided. For example, the light checker which monitors the headlamp - if your dipped beam filament fails, it switches the main beam on. Now, that's gonna annoy oncoming traffic. So most people disable or remove the unit.

Check that the rear lamp works and that light should stay off. But don't hesitate to ask more questions. Cheers, Raymond
Click to expand...
Thanks the quick reply. It’s the light on the cluster that comes on. So, that’s not normal and I have an issue somewhere? I did check both the front and rear brake switches with a meter and both are open when not activated and closed when depressed.
 
Wrenchmorethanride said:
Thanks the quick reply. It’s the light on the cluster that comes on. So, that’s not normal and I have an issue somewhere? I did check both the front and rear brake switches with a meter and both are open when not activated and closed when depressed.
Click to expand...
If it's the rear lamp failure warning, it relates to the rear light, not the brake light. They are both the same bulb - two filaments. The warning is supposed to tell you the rear light filament is not on - either busted or disconnected.
 
Last edited:
It could be the light checker. I think there’s a thread about that on here?
 
If I understand right your light is a “light failure indicator”. I have a couple of different year models, on one it’s an indicator for worn brake pads, the other indicate that I’m using the brake(s). In this case I see a couple of culprits, as mentioned the brake light switch - also the front as the front brake light switch get power from the same brown wire ( if you have the original harness), if it’s not either of those it’s most likely in the light checker box ( probably located under the seat somewhere close to the battery box). I do not have a diagram for that unit and I’m not sure how it works, however the R/B and the Y share tail brake light and the indicator in the dash. I would measure if there are any resistance between those. I would think there should be resistance. Check it out and let me know. When I get back in the garage I’ll try to measure on the once on my bike and a few extra I have.
 
Niels B said:
If I understand right your light is a “light failure indicator”. I have a couple of different year models, on one it’s an indicator for worn brake pads, the other indicate that I’m using the brake(s). In this case I see a couple of culprits, as mentioned the brake light switch - also the front as the front brake light switch get power from the same brown wire ( if you have the original harness), if it’s not either of those it’s most likely in the light checker box ( probably located under the seat somewhere close to the battery box). I do not have a diagram for that unit and I’m not sure how it works, however the R/B and the Y share tail brake light and the indicator in the dash. I would measure if there are any resistance between those. I would think there should be resistance. Check it out and let me know. When I get back in the garage I’ll try to measure on the once on my bike and a few extra I have.
Click to expand...
I did some more checking and have some more info to share.

I checked both the front and rear brake switches. When each is activated the brake light (the one at the rear with tail light) goes on. It goes off when brake is released. So, that seems to be working normally even though the warning light stays on on the cluster.

I did check ground continuity from rest tail light to warning light on cluster and it is good. Didn’t have time to check others.

Another clue. I don’t have a battery that fits in the bike yet (it’s on order, be here in a couple of weeks). I’ve been using another battery and running jumper wire from it to the connections under the seat. The jumper wire is romex wire you’d use to wire in a house. This setup barely gets the engine to turn over and not enough to start. It does get electrical power to run lights, horn, etc.

Finally, I remembered I had a video from about 6 months ago when my brother visited of the bike running. He has a 650 as well. He wanted to see if it ran. I said I don’t have battery but he had one of those portable jumpers. We connected that and got her running. I looked at that video to see if the cluster warning light was on. It was not on while the bike was running. Unfortunately I don’t have any video of just the key on but not running.

I also checked for a wear pad sensor for brakes, didn’t see anything like that on either front or back brakes.

I did find the light checker box under the seat (gray box).

Given what the know so far I’m thinking there are 2 possibilities. 1. My rigged up battery setup is not getting good enough power to the bike and is causing the warning light to come on. 2. If 1 is not the case then I must have caused some issue when I was working on the brakes recently.
 
I can’t see what damage you could have done working on the brakes - maybe be patient and wait till you get the battery. I know a weak battery or lack of power causes issues to other function such as blinkers not blinking ( just stay on ) maybe the light checking box don’t act as it should unless it gets full power.
 
Niels B said:
I can’t see what damage you could have done working on the brakes - maybe be patient and wait till you get the battery. I know a weak battery or lack of power causes issues to other function such as blinkers not blinking ( just stay on ) maybe the light checking box don’t act as it should unless it gets full power.
Click to expand...
I’m going to be away the next 10 days or so. I’ll have the battery when I get back and see what happens. Thanks!
 
I have a 78 and mine is just the warning to the light filiment not pulling enough current. Thus if you have LED tail light it will always be on.
Mine sometimes comes on when I power up ignition, set to run and BEFORE I start the bike. Once I start it, its fine.
Since its sensing current, if your battery voltage is down, I'm guessing may not pull as much current as bike running.

I had issue with turn signals not flashing w/o the bike running. As suggested by members here, Cleaning up the electrical connections (at each connector) helped that. Ignition switch contacts, run/stop contacts, the connectors in the headlight. Bullet connectors to the tail light, turn signals etc.
 
Melnic said:
I have a 78 and mine is just the warning to the light filiment not pulling enough current. Thus if you have LED tail light it will always be on.
Mine sometimes comes on when I power up ignition, set to run and BEFORE I start the bike. Once I start it, its fine.
Since its sensing current, if your battery voltage is down, I'm guessing may not pull as much current as bike running.

I had issue with turn signals not flashing w/o the bike running. As suggested by members here, Cleaning up the electrical connections (at each connector) helped that. Ignition switch contacts, run/stop contacts, the connectors in the headlight. Bullet connectors to the tail light, turn signals etc.
Click to expand...
Thanks. Fingers crossed it’s just the battery. Will update in a couple of weeks when I get back.
 
Update!

I got the new battery, long story short I got it running…. Not great but running.

The light does go out once it’s running, so that mystery is solved. Thanks to all for your help.

Now on to figuring out how to get her running better. I’ll do some research and post if I can’t figure it out.
 

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