No marker lights when headlights are on

did you figure it out i have the same problem????

 

See if one of the circuit breakers for the trl taillights or marker lights is popping.

 

Might be a faulty circuit breaker, kinda weird, now I'm intrigued.

 

may be bad grounding

 

I just bought an '06 Columbia and first day out (while driving at night in the rain) I learned of this similar issue. Currently having the dealer look into it. But basically, if my headlights are on then my interior dash as well as trailer lights turn off. But if I flip the switch down to the marker position everything comes on except the headlights. ...weird. Hopefully a simple fix. The windshield also leaks pretty bad which may be the culprit. I'll know within a day or two. Interested to see how the OP's situation develops.

 

Any update on this, I just started having the same problem.

 

For me, at least, it turned out to be a short in my left side marker. Pretty much all the electrical to my rear was routed through that same wire bundle. I have no idea how that affected my dash but since i replaced that socket and bulb a few weeks ago I haven't had any problems. If it does come back then i'll try replacing the marker interrupt or headlight switch next.

 

does it happen with the trailer hooked up? or all of the time?

 

Try unplugging the tail lights on the truck. See if they work with the tail lights not plugged in. Sounds weird, but is a common problem.

Martin