EX Shuts Tail Light Off

bluefxstc

Well-known member
Likes
547
Location
Boise, ID, United States
#1
Found out today my 2018 EX’s (#027) tail light isn’t working. Brake light works, but no tail light. Initial thought was no biggie, bad bulb, I will replace it and all is well. Guess what, it is not the bulb. Clean the bulb and socket, which is probably the cheapest socket I have ever seen, put it back together and still no tail light, unless the key is turned on with the headlight switch in high beam. If you turn the key on, with the headlight switch in the high beam position, the tail light works until you switch to low beam, and then the tail light goes out. Switch back to high beam and the tail light stays out. Thinking it is a resistance check in the computer, I figure a resister in parallel with the low beam headlight element, to match the resistance of the high beam bulb element, and all will be good. Not so quick, tried numerous combinations of resisters from 1K down to 1 ohm with no luck. This is a completely stock EX. Stock headlight and stock tail light, the only changes I have done to the bike are tires, mirrors and a tank bag so nothing that would impact the electrical system. This is very similar to the problem that @WoodsWeapon had with his NCR tail light setup.

The good: I found out about the problem before anything bad happened.

The bad: I have been riding the bike to work, and for about the past month it has been dark in the morning when I am going to work. I have no idea if the tail light was working or not. I am not happy about that. The fact that Alta has some sort of software check on the resistance or load of a circuit, and then shuts of a piece of mandatory safety equipment like a tail light without some sort of warning, is unacceptable, at least to me. Maybe you could say I should have checked the tail light before I left every time, but I don’t do that with any of my vehicles, and don’t think I should have to. Additionally, if I started and checked while the bike had high beam selected, the tail light would be working, until I switched to low beam and then it would be out until switched the bike off and restart it. I also use high beam to flash crossing traffic to help ensure they see me, so this is a major concern for me. Flash crossing traffic with the headlight so they don’t pull out in front of me then get rear ended because I don’t have a tail light, decisions decisions.

Future options. Going to continue trouble shooting to see if I can figure out a solution. Anyone have any ideas? Option two is to run with the head light in high beam all the time as the tail light seems to work with that all the time. With this option you can’t switch out of high beam because as soon as you do, you lose the tail light. Options three, take it back for warranty service. This may fix the tail light problem, but will probably involve a reflash which will cause me to lose the higher regen I currently enjoy, want, and use extensively in map 3. Will probably have to do it because safety of a tail light is more important than regen, but not looking forward to the change so will be working on option one for a while. Sucks that I have to accept a less capable platform to get a motorcycle that has a consistently operating tail light.

Anyone have ideas on a solution that doesn’t involve a reflash? @Judaslefourbe? It seems to be related to the load of the headlight shutting off the tail light. Given the limited info we have on how these bikes operate, not sure why that would happen. I also can’t figure out why Alta would think it is a good idea to shut off the tail light, without a warning light, when the bike senses a load is lower than expected, makes no sense to me at all.
 

leeo45

Geezer in denial
Likes
364
Location
Lake Hartwell, SC
#2
I just went and checked my '19 EXR since I also ride it on the street in the dark. The taillight stays lit regardless of headlight position and after multiple hi/low/hi/lo switches. In theory, I have the latest firmware on the bike so that might be one solution.

However, I agree that regardless of firmware version, the system shouldn't be shutting off a legally required light and safety device on an EX, EXR, or SM without some type of error or warning light.

Hope it turns out to be an easy fix.
 

WoodsWeapon

Well-known member
Likes
240
Location
USA
#5
My problem has been fixed, although Im not sure how. I cut my main tailight harness and added a weatherproof plug in the middle of all 9 wires to make tailight quickly removeable. Ever since then, its been working like it should. What I would suggest is unplugging the harness from under the seat, near the “fuel tank”. Power bike up without plugged in, then turn off and plug harness back in and repower. In all of the hassles Ive gone through with the taillight, I believe everytime its unplugged the system relearns itself somehow.
 

bluefxstc

Well-known member
Likes
547
Location
Boise, ID, United States
#6
Thanks @WoodsWeapon, I appreciate the input, unfortunately, that didn't seem to work for me. I tried it tonight with no change, but will try again tomorrow when I can run it around my pasture with the tail light disconnected to see if time has any impact. What does seem to work is to start the bike with the head light in high beam and then shut it off with it still he high beam. I can then select low beam, start the bike, and about 90% of the time the tail light will will work. If the tail light is working and I select high beam, the tail light will turn off when I select low beam. It also doesn't work if I am in low beam, with the tail light working, then select high beam and turn it off. If I do that the tail light will be off when I turn the bike on. I have to turn it to high beam, turn the key on so the bike is on with the tail light working, then turn the bike off with it still in high beam. It is like the bike throws a software switch for the tail light circuit to work with it in high beam and to not work in low beam. Not sure what is going on with that. I am leaving to ride the NMBDR the last week of the month, so if I don't have something figure out by then, I will drop it off at the dealer and let them work on it. I will be gone for about 2 weeks so hopefully they will have time to figure it out. Thank God I bought a Alta with a local dealer, and not something else without local dealer support. It would really suck if I had to haul the bike 6 hours to get warranty service.
 

bluefxstc

Well-known member
Likes
547
Location
Boise, ID, United States
#8
What bulb are you using? 1157?
I think it was a 1157, but didn't check the number. It is the bulb that Alta put in it originally. Pulled it out, took a look at it and it looked good so checked continuity of elements and it was good so I put it back in after cleaning it. There was a lot of dust on it. There is no back to the socket so all the dust and dirt that gets past the fender guard collects on the grease they put on the bulb terminals.
 

datadog

Well-known member
Likes
288
Location
USA
#9
The OEM bulb is a 7568 rather than an 1157. This is the European equivalent. Might I suggest that you purchase a new 7568 bulb and try it before the trip to the dealer? It might not solve the problem, but, then again, it could. The issue here is what is called inrush current. Our software based circuit protection measures inrush current and turns off certain circuits if that value is lower or higher than expected. It works well most of the time, but occasionally throws a false alarm. I'd like you to try a new 7568 bulb with clean contacts or even a new 1157 (this has worked in the past) and see if that solves your issue - maybe you wouldn't have to trek to your dealer.
 

bluefxstc

Well-known member
Likes
547
Location
Boise, ID, United States
#10
Will do, thanks for the suggestion. I will stop by an auto part store on my way home and get a new bulb. Can I purchase a 7568 at a US auto parts store or will I have to go with an 1157? Thanks again for the suggestion, awesome idea.
 
Likes
21
Location
PDX
#16
I just put an led tail light on mine and ran the accessory light power back to the tail light. I ran one wire through the front brake switch(I only have a hand rear brake and alta didn't provide a switch for that one) and one wire straight back. Works pretty well. I managed to use all the same connectors so I didn't have to cut any wires.
 

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