Electrical issue
Electrical issue
Ok, I'm having a very weird electrical issue with the rear lights on my bike. I have an aftermarket side mounted tail light that has a module to convert the turn signals to running and turn signals. Or at least that is how it work up until now. I recently did yet another repair job to my left turn signal wires and when I hooked everything back up it was all working. Went out just a while ago and started her up to find I had no left running light or turn signal. Took everything apart just to verify I didn't have a pinched or shorted wire. Everything tested fine. Took the plug for the right side and plugged into the left side and it would not work. I checked the voltage on the pins off the circuit board and with the key on but bike not running I was getting 10 volts on the right (brown wire on main harnes) and only 6 volts on the left (purple wire on the main harness). I check this in several places and was getting pretty much the same reading at every place I could check. Looking through the manual I noticed that the security system possibly uses the hot wire off the left turn signal in some fashion or another. I have no clue if the security system has any play in this because I bought the bike used and didn't get any key fobs for the bike. After playing around a little more I now don't have the running light's on either side of the bike but both turn signals are working now. I re-measured voltage at the circuit board and now getting 6 volts on both the left and right turn signals. Anyone have any ideas on this one? Could a loose ground wire somewhere be causing a drop in voltage across the turn signals. If there is a security system on the bike (pretty sure there is) can it be removed completely without any affects?
I guess it could be possible the module that converts the lights is going bad. At the main harness there is no power on the brown and purple wire until you put the turn signals on. With the module plugged in I only get 6 volts on these two wires until I put the turn signal on and then I get 12 volts. I'm still wondering if there could be a ground issue somewhere?
Road Warrior
Joined: Jul 2011
Posts: 1,345
Likes: 1
From: coastal NC
I had a somewhat similar issue caused by a module like that on my bike. I bought it used, as you have, and it had one of those modules on it that would make the rear turns act as brake lamps. All of a sudden I had either no brakes or no turns on one side or another. No warning signs, it just happened. Tapped the module a few times and everything started working. Tapped it again, and stuff stopped working again. Needless to say, I unplugged the danged thing and reconnected the factory connectors and everything has been fine for months. Hope this helps ya.
I had a somewhat similar issue caused by a module like that on my bike. I bought it used, as you have, and it had one of those modules on it that would make the rear turns act as brake lamps. All of a sudden I had either no brakes or no turns on one side or another. No warning signs, it just happened. Tapped the module a few times and everything started working. Tapped it again, and stuff stopped working again. Needless to say, I unplugged the danged thing and reconnected the factory connectors and everything has been fine for months. Hope this helps ya.
Thanks.
I'll be working on it today. I have to modify the brake light as currently the wires are soldered into the module. The previous owner did a bit of a hack job when bobbing the rear fender and relocating the brake liight to the side. My only fear with not having the turn signals as running lights is only having the tail light lit up back there. Because the bike has been lowered the tail light hides behind the trun signal just a little so I will have to watch my back side while riding through town.
Trending Topics
Road Warrior
Joined: Jul 2011
Posts: 1,345
Likes: 1
From: coastal NC
Gotcha. Worst case scenario, get another one of those little module do dads if it is your problem. Keep us updated.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Removed the module and put everything back together. Everything works just fine minus not having the rear running lights. I had to get a little creative on getting the tail/brake light hooked up but I think it will be just fine. Since the tail light is mounted on the bottom shock mount and gets a lot of vibration I decided to go with a LED tail light. Going to see how this works out and if I have any issue I will buy another module to get the turn signals back to running lights. This is just so I will be more visible.