Troubleshooting No Trailer Power or Running Lights with Hopkins 7 Round to 7 Blade RV Adapter

Published 10/10/2019

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Question:

I have a Pollak 7 pin plug-in on my truck I have a 7-way RV plug on my trailer I have a HM47425 adapter 7 way to 7 round pin but Im not getting a power source or my running lights is there a diagram for the 7 pin on what wires control what cuz it just has color abbreviations on where wire goes thank you

asked by: Frank D

Expert Reply:

It sound like some of the functions on your trailer wiring are not connected in the standard pin locations which is what both Pollak and Hopkins use.

On your trailer, locate the wires and pin location by function only as color coding is not standard across all manufacturers. Start by testing the 11:00 and 1:00 pin positions on your trailer with a circuit tester like # PTW2979; this is most likely where your wires are crossed. There could also be a short between these two circuits since they are side by side so inspect all wires going to those pins and replace/repair if necessary.

I recommend testing all pin functions just to make sure they are connected correctly and change their location if necessary to match the diagram below.

I have also attached a Trailer Wiring FAQ at the bottom of the page which includes additional diagrams and helpful information.

expert reply by: Carla M