I installed aftermarket 3 wire, marker/turn signal lights last spring. Everything was running great up until this morning... Right now all 4 turn signals work, but only the front left is lit up as a marker light. For whatever reason the other three will not light up unless the turn signal is activated.

My only guess what caused the problem is I rode in the rain last week, and this morning was the 1st time I've been on it since. It's cold here in Ohio, so I'd appreciate some good advice before I rip too much stuff apart. Thanks!!!

 

Bulbs or LED? Id check the bulb first obviouslly, then just start checkin current backwordswith a 12v tester

 

Bulbs. Hmmm...do the bulbs have two filaments in the 3-wire marker light/turn signals? Maybe one of the filaments went out in those 3 bulbs. I didn't think of that till just now! I'm having a "duh" moment. I'll check when I get home.

 

Yes, they are dual filament.

The marker/parking light is the smaller filament and the larger is for the signal.
Your smaller filaments may have shorted out..

 

Sure enough one of the filaments for the right front bulb was blown. My rear marker lights/turn signals are single filament and both were fine. Of course all local places I called do not have the bulb so I had to order them online So with the left front running light filament blown, do you think that is what is causing the rears to not to light up as running lights?

 

Are you sure that the rear bulbs ever came on as running lights? Mine do not. Also, it is not possible for a single filament bulb to operate in a dual intensity role (ie running lights are dim, but flash brighter for turn signal).