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Discussion Starter #1
Greetings all.

I just found a thread regarding brake lights being stuck on, even with the key off. I'm not sure if that thread was completed and no longer active so I'm reposting here. It appears that I have the same issue on my 2007 LT. A week or so ago I got off the bike and attempted to put the center stand down and just got the blinking light on the dash. I put the side stand down and got off the bike and saw that the brake lights were on (key was off). I have added auxiliary brake and directional led lights along my top trunk. These are connected directly to the bikes original equipment lights. I also put some of those accent lights on but they have been disconnected and have no contact with the bikes brake lights. I was unable to get to the dealer for a couple days so I disconnected the ground from the battery and put the charger on the battery. (if I simply used the accessory plug on the bike the brake lights would stay on and the battery would not charge) I took it in to the dealer and was told that something in the additional lights had shorted out, they "cleaned it up" and gave me the bike back and the brake lights were off. I road it home and low and behold the lights were back on. I disconnected all the extra lighting wiring and they were still on, which led to my search of the site and to this thread.

After reading the thread I went out to check to see if there was any accumulated dirt or debris causing the switches to malfunction or if the switches could be heard to click as the pedal or hand brake lever were pressed. Naturally when I went to the garage and connected the battery the lights were not on. I listened to the light switches on the rear and front brakes. I could hear clicking from each switch when I pressed on the foot pedal or squeezed the handle. I am assuming this means that the switches were working. there did not appear to be any dirt, debris or anything else blocking the switch button on the rear brake. I turned the key on and the brake lights work with both the pedal and handle. (the servos all work) When I shut the bike off the lights went out.

I took the bike out the next morning and the brake lights came on and stayed on. So it was back to disconnecting the ground and putting the battery on the charger.

Is it possible that one of the switches is going and that's why I'm getting the intermittent problem? Could the relay be bad if the lights go out like normal, or if it were bad would they always be on? Or should I just change out both switches and the relay? Naturally I just filled the tank :)

thanks for any help

Joe Rowland
 

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Greetings all.

I just found a thread regarding brake lights being stuck on, even with the key off. I'm not sure if that thread was completed and no longer active so I'm reposting here. It appears that I have the same issue on my 2007 LT. A week or so ago I got off the bike and attempted to put the center stand down and just got the blinking light on the dash. I put the side stand down and got off the bike and saw that the brake lights were on (key was off). I have added auxiliary brake and directional led lights along my top trunk. These are connected directly to the bikes original equipment lights. I also put some of those accent lights on but they have been disconnected and have no contact with the bikes brake lights. I was unable to get to the dealer for a couple days so I disconnected the ground from the battery and put the charger on the battery. (if I simply used the accessory plug on the bike the brake lights would stay on and the battery would not charge) I took it in to the dealer and was told that something in the additional lights had shorted out, they "cleaned it up" and gave me the bike back and the brake lights were off. I road it home and low and behold the lights were back on. I disconnected all the extra lighting wiring and they were still on, which led to my search of the site and to this thread.

After reading the thread I went out to check to see if there was any accumulated dirt or debris causing the switches to malfunction or if the switches could be heard to click as the pedal or hand brake lever were pressed. Naturally when I went to the garage and connected the battery the lights were not on. I listened to the light switches on the rear and front brakes. I could hear clicking from each switch when I pressed on the foot pedal or squeezed the handle. I am assuming this means that the switches were working. there did not appear to be any dirt, debris or anything else blocking the switch button on the rear brake. I turned the key on and the brake lights work with both the pedal and handle. (the servos all work) When I shut the bike off the lights went out.

I took the bike out the next morning and the brake lights came on and stayed on. So it was back to disconnecting the ground and putting the battery on the charger.

Is it possible that one of the switches is going and that's why I'm getting the intermittent problem? Could the relay be bad if the lights go out like normal, or if it were bad would they always be on? Or should I just change out both switches and the relay? Naturally I just filled the tank :)

thanks for any help

Joe Rowland
Joe, if you read through the entire other thread, have you tried isolating the ABS as jzeller suggested in the post immediately before yours, picture included? I would do that to isolate the unit and make sure you don't have a bad ABS unit before going any further. If the brake lights stay lit, you have another issue with possibly the relay sticking or a short. Don't have my book in front of me to research the wiring at the moment and I don't have that model so there are others who have far more experience with it than I do.
 

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Discussion Starter #3
Hi Gordon. I'm going to give that a try. I just thought that since the problem is intermittent it wouldn't be electrical but mechanical. And the new stop light switches are about $60 each rather than thousands :) I'll keep trying. It too bad my dealer only has one "LT guy" and he's in training so bringing it in is not an option until next week. Since this is my only means of transportation right now I need to find a solution.

thanks again,
Joe
 

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Hi Gordon. I'm going to give that a try. I just thought that since the problem is intermittent it wouldn't be electrical but mechanical. And the new stop light switches are about $60 each rather than thousands :) I'll keep trying. It too bad my dealer only has one "LT guy" and he's in training so bringing it in is not an option until next week. Since this is my only means of transportation right now I need to find a solution.

thanks again,
Joe
Another thing you can do is to measure the switches with an ohm meter. In the other thread, one poster mentions that they are normally closed not normally open but I can't confirm this so until proven incorrect, I will accept that as no one else in that thread contradicted it. If you can trace the wires back to the plugs, you can test the switches. If they are normally closed and one is bad, simply unplugging them won't make the brake light go out if the switch is bad, it will make the light go on so it needs to be tested with a meter. The switch can still click and not work. That test is mostly to make sure the adjustment is not holding it open all the time.
 

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Discussion Starter #5
Another thing you can do is to measure the switches with an ohm meter. In the other thread, one poster mentions that they are normally closed not normally open but I can't confirm this so until proven incorrect, I will accept that as no one else in that thread contradicted it. If you can trace the wires back to the plugs, you can test the switches. If they are normally closed and one is bad, simply unplugging them won't make the brake light go out if the switch is bad, it will make the light go on so it needs to be tested with a meter. The switch can still click and not work. That test is mostly to make sure the adjustment is not holding it open all the time.
I'll give that a try next. So if I'm understanding this I should get a reading showing a closed circuit when the pedal is not depressed and an open one with the pedal depressed? I've done most of the mechanical service on the bike including replacing the clutch, but on the current electrical stuff I'm a bit of a novice.

thanks again,

Joe
 

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I'll give that a try next. So if I'm understanding this I should get a reading showing a closed circuit when the pedal is not depressed and an open one with the pedal depressed? I've done most of the mechanical service on the bike including replacing the clutch, but on the current electrical stuff I'm a bit of a novice.

thanks again,

Joe
If it is indeed normally closed, that is correct. At the very least, you should be moving from a closed to an open state as the switch moves regardless of normally closed or open types. If you don't get a transition, the switch is bad. I was making the distinction because if a normally closed switch is bad ( open ) and you unplug it, the state will not change so the brake light would remain on. As long as you can measure the transition from closed to open, the switch is working at least at the time of testing. This is an intermittent issue though.
 

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The fact that it is now intermittent leads me to a sticking relay but that is very rare. If the ABS electronics was at fault it would not go away. So it is either a switch at the edge of adjustment or a loose wire somewhere in the circuit. The switches are normally closed so an open (either switch or loose wire) will make the ABS think the brakes are applied. In the mean time you can pull fuse F12 to stop the lights while the bike is off and charging. It is the only 15 Amp fuse in the box closest to the seat latch. Easier than pulling the (-) terminal.

(reply for your other post) If you try the procedure to disconnect the ABS do so only after you have confirmed the switches are operating OK. If the lights stay on with ABS connector off then it is a stuck relay. If they go out then there is an electrical fault on the ABS circuit card. Tyler at Module Masters has had good luck fixing the circuit cards so it may not be an expensive fix if that is the issue.
 
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Discussion Starter #8
Well here's the status. Per John's suggestion I pulled the brake light fuse rather than disconnect the battery every time I stopped the bike. Many thanks. The morning after the first time that was done I put the fuse back in and the brake lights came on. I got on the bike, started it up and the brake failure lights came on. I stopped, shut it down, started it back up and the lights went out. It also shut the brake lights off!! I had made an appointment to take it into another dealer that afternoon. I rode around on some errands and the brake lights stayed off the whole time and were off when I got to the dealer. They couldn't replicate the situation until the second day they had the bike. Then they checked things out and found the ABS control panel ok. The switches seemed ok. They did find some corrosion on the relay which they cleaned off and reinstalled and the lights went out. I picked the bike up and rode it for a day and all things were ok. The second day the lights were back on when I got off the bike. I called and the service guy said he'd notify bmw and see what they say. I asked how power could possibly be going to the fuse for the lights if the ignition was off. He had no idea.

In the mean time it was back to unplugging the fuse. Once again when I plug it back in the lights go on, then out.

If any of you folks have any ideas I'd be interested. As I said, I can take the clutch out and put a new one in but I'm a novice when it comes to all this new fangled electrical stuff. When I first started on cars the only electrical was the battery, starter, generator, coil and spark plugs. LOL. I think we used candles for head lights :)

Oh and I fixed the low idle thanks to another member's post in that area, the reset procedure was all that was needed, not a new idle actuator switch as recommenced by the dealer. geesh!

thanks again,
Joe
 

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Discussion Starter #9
The brake lights are still on after some fiddling and fuse removal and replacement. When all this happens the ignition switch is off. This seems to me that something is causing power to be supplied to the line that goes to the hot side of the fuse. I am at a loss to figure out how that can be. The last service guy said that all power is off with the ignition switch off. I asked about the remote locking system, since, with the ignition off, I can hit the button on the remote and the locks lock, using power from somewhere, and the directional lights flash. He claimed that this power comes from its own source and not that bike battery????

Is anyone aware if there can be some short causing power to go to the wire that goes to the fuse? I'm trying to find a wiring diagram but there is none in the Service Manual. 454 pages and no diagram, weird.

Joe
 

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The brake lights are still on after some fiddling and fuse removal and replacement. When all this happens the ignition switch is off. This seems to me that something is causing power to be supplied to the line that goes to the hot side of the fuse. I am at a loss to figure out how that can be. The last service guy said that all power is off with the ignition switch off. I asked about the remote locking system, since, with the ignition off, I can hit the button on the remote and the locks lock, using power from somewhere, and the directional lights flash. He claimed that this power comes from its own source and not that bike battery????

Is anyone aware if there can be some short causing power to go to the wire that goes to the fuse? I'm trying to find a wiring diagram but there is none in the Service Manual. 454 pages and no diagram, weird.

Joe
If I understand correctly, you have not replaced anything yet. jzelller is one of the brightest and knowledgeable people on this forum relating to LT issues and isn't going to purposefully steer you wrong. With the cost of the relay being low, I would go for it and see if it changes anything. Unless I am reading the MAX BMW parts fiche wrong, they are less than the cost of that $60 switch that you were not worried about. It sure does sound like a sticking relay. Why not replace it before you spend a lot of shop time and $$$
 

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Discussion Starter #11
Hi Gordon,

Not sure if you read my last post, but it does appear to be the relay. So it's going back to the dealer who took it all apart to remove the relay and "clean" it and replace it. Why they didn't just put in a new one is beyond me. Like you said, it's maybe $70!! Oh well.

Joe
 

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Hi Gordon,

Not sure if you read my last post, but it does appear to be the relay. So it's going back to the dealer who took it all apart to remove the relay and "clean" it and replace it. Why they didn't just put in a new one is beyond me. Like you said, it's maybe $70!! Oh well.

Joe
I did see your last post and the mention of some corrosion being cleaned but as you said, the relay was not replaced. If it is the yellow one, that looks to be $21.79 and blue is $33.46, Grey is $18.38 black is $18.38. Not sure which one actually handles the brake lights but that can be figured out pretty easily, probably listed in the clymer manual but I haven't researched it yet. The turn signal and starter relays are much more expensive. I hope this fixes it as shop time adds up pretty fast for a $22 relay and an LT and you have had it in several times already.

Good luck this time around.
 

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The relay and fuse F12 are HOT all the time key or no key. That is why when the relay sticks the lights are on. There are several circuits on the LT that are always hot and then several that are on with the key (this is "switched" power). Not everything is controlled by the key. It is the $20 relay so they should have just replaced it. Cleaning a relay requires burnishing tools and most dealer don't have those. Using sandpaper is not a good alternative, in fact it can cause a relay to stick worse.
 

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Discussion Starter #14
The relay and fuse F12 are HOT all the time key or no key. That is why when the relay sticks the lights are on. There are several circuits on the LT that are always hot and then several that are on with the key (this is "switched" power). Not everything is controlled by the key. It is the $20 relay so they should have just replaced it. Cleaning a relay requires burnishing tools and most dealer don't have those. Using sandpaper is not a good alternative, in fact it can cause a relay to stick worse.
Hi John,

Thanks for the info. The bike is going back to them tomorrow morning. I have no idea why they wouldn't have replaced the $20 relay, but they're going to have to do it on their dime since they had everything off that needed to be off last time. I'll keep everyone posted. What a pain in the butt!

thanks again,
Joe
 

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Discussion Starter #15
The relay and fuse F12 are HOT all the time key or no key. That is why when the relay sticks the lights are on. There are several circuits on the LT that are always hot and then several that are on with the key (this is "switched" power). Not everything is controlled by the key. It is the $20 relay so they should have just replaced it. Cleaning a relay requires burnishing tools and most dealer don't have those. Using sandpaper is not a good alternative, in fact it can cause a relay to stick worse.
Hi John,

Perhaps my limited knowledge of the sophisticated electrical systems on today's bikes has me confused. If the relay and fuse are always HOT then the brake lights would be on all the time. Or am I not understanding this. If the fuse is "hot" wouldn't that mean that power is going through the fuse to the brake lights all the time? I thought it would be the application of the brakes that power would transmit the 12v to the fuse and to the lights? I know the power in some way goes through the ABS system and to the relay, but shouldn't that then close the relay and then transmit the 12v to the lights?

Joe
 

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Hi John,

Perhaps my limited knowledge of the sophisticated electrical systems on today's bikes has me confused. If the relay and fuse are always HOT then the brake lights would be on all the time. Or am I not understanding this. If the fuse is "hot" wouldn't that mean that power is going through the fuse to the brake lights all the time? I thought it would be the application of the brakes that power would transmit the 12v to the fuse and to the lights? I know the power in some way goes through the ABS system and to the relay, but shouldn't that then close the relay and then transmit the 12v to the lights?

Joe
The relay can be hot and the fuse can be hot all the time and as long as the relay is not closed, the lights will not be on. The function of a relay like this is to allow a small amount of current from say the ABS controller to control a larger amount of current to power all the bright brake lights and not need big transistors and heat sinks inside the ABS. The trigger wire on the relay is controlled by something else like a small transistor in the ABS controller triggered by the brake switches or a pressure switch in the brake lines. Those feed signals are off when the key is off but if the relay sticks closed, the lights never go out even though the signal from the ABS controller is no longer present. Once the relay un-sticks, the lights go out and may function normally for a time until it sticks again.

It may be that the added lights on your bike were too much for the relay to handle and that is why it is now sticking. Not sure how yours was set up but most people use a fused direct link from the battery to power additional lighting and use a separate relay triggered off an aux circuit if on all the time or off the brake lights to power bigger lights without over heating the stock internal relay. I don't think BMW over engineered too many things like that because some of their wires are only just large enough to handle what is being fed by them. Hope that helps.
 

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Discussion Starter #17
Hi John and Gordon,

I took the bike back in this morning to the dealer service. They replaced the Stop Light Relay (to their credit at no cost to me, thank you Riverside BMW). Got the bike back, everything off, including the brake lights. Rode the bike back home, shut everything off and the brake lights are back on!!!!! I'm ready to push this pos off a pier and go buy a Harley. Any other suggestions as to why the lights come back on. I have really had it with this. I'm at the point where I pull all the brake wiring off and just put a line from the battery to the switches and to the lights like back in the old days. It's really pretty sad when what should be a simple matter turns into this mess.

thanks again for all your help and support,

Joe
 

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Hi John and Gordon,

I took the bike back in this morning to the dealer service. They replaced the Stop Light Relay (to their credit at no cost to me, thank you Riverside BMW). Got the bike back, everything off, including the brake lights. Rode the bike back home, shut everything off and the brake lights are back on!!!!! I'm ready to push this pos off a pier and go buy a Harley. Any other suggestions as to why the lights come back on. I have really had it with this. I'm at the point where I pull all the brake wiring off and just put a line from the battery to the switches and to the lights like back in the old days. It's really pretty sad when what should be a simple matter turns into this mess.

thanks again for all your help and support,

Joe
Sorry to hear that Joe. If the bike was close enough to me for diagnosing, I would be running a few wires off the relay to a point where I could measure them when the issue is happening. I would want to know if the relay is energized or not when the lights are stuck on. If the relay is energized, then the issue is in the control circuit.

I will look at the schematics tonight to see if the relay provides 12V to the lights or if it simply provides a ground to the circuit and the 12V is always at the light sockets. It could do either. The relay may also be the same and a ground is provided to complete the circuit rather than a 12V signal. If it is a ground that is provided, then you have a short somewhere before the relay or if it grounds through a transistor or relay in the ABS controller, an issue at that location causing the relay to remain energized. Shorts normally remain shorts until they are fixed. Mine is an 01 without the servo brakes so there is probably not much I can test in a direct relation to your year on my own bike. John may have some better ideas and have a knowledge of the brake lights and ABS system already to send you in a different direction.
 

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Discussion Starter #19
Sorry to hear that Joe. If the bike was close enough to me for diagnosing, I would be running a few wires off the relay to a point where I could measure them when the issue is happening. I would want to know if the relay is energized or not when the lights are stuck on. If the relay is energized, then the issue is in the control circuit.

I will look at the schematics tonight to see if the relay provides 12V to the lights or if it simply provides a ground to the circuit and the 12V is always at the light sockets. It could do either. The relay may also be the same and a ground is provided to complete the circuit rather than a 12V signal. If it is a ground that is provided, then you have a short somewhere before the relay or if it grounds through a transistor or relay in the ABS controller, an issue at that location causing the relay to remain energized. Shorts normally remain shorts until they are fixed. Mine is an 01 without the servo brakes so there is probably not much I can test in a direct relation to your year on my own bike. John may have some better ideas and have a knowledge of the brake lights and ABS system already to send you in a different direction.
Hi Gordon,

I'll have to take things apart but as I recall the ground wire is brown. I'll see if I can track it down tonight. If there is always 12v going to the lights and the relay provides the ground to turn them on, then if I were to disconnect the brown wire from the bulb it should go out. If I then attached a wire to the frame and touched it to the bulb it should light up again, correct? I'll check the wires from the auxiliary lights to see if a wire on the ground side has stripped insulation allowing the ground to be transmitted to the brake light. Although if that were the case why would they every go out?

Thank you again and I'll wait to hear from you regarding the other info.

Joe
 

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Discussion Starter #20
Sorry to hear that Joe. If the bike was close enough to me for diagnosing, I would be running a few wires off the relay to a point where I could measure them when the issue is happening. I would want to know if the relay is energized or not when the lights are stuck on. If the relay is energized, then the issue is in the control circuit.

I will look at the schematics tonight to see if the relay provides 12V to the lights or if it simply provides a ground to the circuit and the 12V is always at the light sockets. It could do either. The relay may also be the same and a ground is provided to complete the circuit rather than a 12V signal. If it is a ground that is provided, then you have a short somewhere before the relay or if it grounds through a transistor or relay in the ABS controller, an issue at that location causing the relay to remain energized. Shorts normally remain shorts until they are fixed. Mine is an 01 without the servo brakes so there is probably not much I can test in a direct relation to your year on my own bike. John may have some better ideas and have a knowledge of the brake lights and ABS system already to send you in a different direction.
Hi again Gordon,

If you want to reach me directly you can e-mail me at [email protected] or text or call at 714 588-4041.

thanks,

Joe
 
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