Yellow Side Marker Lights Will Not Light Up on Trailer Towed by a 2006 Dodge Ram 1500

Question:

I bought the 7 way trailer connector for my 2006 dodge ram 1500. It already had a 4 prong wire harness for trailer. Prior to installing 7 way, when the trailer was connected to truck,it would light up tail lights but not the running yellow lights on body of trailer. When I installed the 7 way connect and used the plug, same thing. Brake lights worked,turn signals worked but no yellow running lights. What do I need to do to make the yellow marker lights come on? I thank you in advance for any help you may have. The trailer is equipped with a 4 prong attachment.

asked by: ward

Expert Reply:

You will need to check to see where the marker lights are wired on the trailer. Trace the wiring to see which pin the wiring goes to on the trailer connector. Then you can use our wiring FAQ article which I have linked for you to determine which circuit they are attached to on the trailer side connector. To come on with the running lights, they will need to be connected to the pin directly next to the covered ground pin on the 4-Way.

If that is how they are wired, it could be that the truck and or wiring harness is unable to support the amperage draw of the additional lights. You can also make sure the lights are properly grounded and there is no corrosion where they are connected.

expert reply by: Michael H