I have a 2003 Dodge Dually 3500 and when I hook up either my goose neck or a bumper pull, the turn signals on both vehicles sometimes quit working. When I unplug the trailer the turn signals on the truck start working just fine.

 

The first thing I would do is check the wiring on the vehicle side of the connector. Do the lights do this if you hook it to someone elses trailer? The common denominator on your problems is the vehicle. My gut feeling is you have a ground problem somewhere in the connection.

 

I ran across the same problem.
Just to verify the problem I ran a ground wire from the trailer ground to the car battery and everything worked. It was either the plug to truck ground or the trailer to plug ground, I can't remember. good luck.

 

Like Grouch said. Try another trailer but i'm guessing you have a short in the trailer. I encountered this not to long ago.

 

Thank You, appreciate your advise, I will definitely check it out.

 

Thank you, for your advise, today I pulled a different trailer and no problem, it must be something with the two trailers I had the problems with.

 

Thank you, for your advise, today I did pull a different trailer and no problem, it must be something with the two trailers I had the problems with. Thanks again.

 

Thank you, for your advise, today I did pull a different trailer and no problem, it must be something with the two trailers I had the problems with. Thanks again.