I have a 2009 Ram 2500 Cummins and my tail lights are not working properly. Only thing working is running light on drivers side. All lights are working properly on the front. I've checked fuses and bulbs and bulb sockets with no luck. Any advice on this problem will be greatly appreciated.

 

HI I have the same truck, my issue is similar- when I turn on the left turn signal all my running lights flash. Saw a video on UTUBE that might help.

 

First off, check your ground connections. a bad ground connection will cause all kinds of nasty issues.