As I have been working on the motorcycle there have been a few electrical issues that I have noticed that will need to be addressed before the motorcycle would pass the annual inspection. One of those issues was with the turn signals. The left turn signals were operating properly, but the right side would light the front turn signal, which would then remain lit, and the rear turn signal would not light up. So, with a small window of time on a rainy afternoon I decided to look into this.
Bulbs appeared to be fairly new and of the correct size, so I switched the front and rear bulbs to see what would happen. Same thing. Front lit and remained steady while the back did not light. This is the correct turn signal operation if a bulb burns out to indicate that you need to replace a bulb, but both of the bulbs are good.
I suspected that maybe the ground wire on the rear signal might be loose or broken, but it visually appeared to be ok. I then got out the test light and connected it to the negative battery terminal. When I touched it to the light socket, it lit up, so there was power getting to the turn signal.
Next up was a look at the wiring diagram. Luckily someone has created a full color version of the wiring diagram online and I was able to plot it to a 24″x36″ sheet of paper to hang on the wall right next to the motorcycle.
What I found next when I started tracing the wires was surprising. The right rear turn signal black wire should join up with the green positive wire that goes to the right turn signal switch and the black wire with white stripe should go to the negative ground wire. The two wires were reversed. Not sure if you would call that a Ground Fault or a Short Circuit, but either way, it’s not going to work.
Corrected wiring connections.
Once the wires were swapped to their correct positions, the turn signals functioned properly.
Not sure how long this might have been miswired or why, but at least it did not cause any damage to the wiring system. Probably would be less error prone if the right wire stayed green all the way to the turn signal, but I am sure that Suzuki only manufactures one turn signal with a black wire and a black/white wire. The left turn signals have a black wire for the positive wire.
I have seen what can happen when an incorrect wiring connection is made. Working at a marina many years ago a new employee was helping me setup a new boat and connected a green ground wire to the positive terminal of the battery. Wasn’t apparent that it caused any damage right away, but later on there was an issue with the gauges in the instrument panel. When I pulled off the panel, many of the small wires had melted their insulation and fused the wires into a large mass. I spent the better part of the day rewiring the instrument panel…