I have an 05 FX4 that the trailer running lights do not work. I've changed the R201 relay and it's still not working. Didn't know if I was overlooking something else. Any words of wisdom?

Thanks,
Matt

 

Are the brake lights working ? Ask as this would point to a missing ground.

The trailer tow parking lamp relay is fed from Fuse F10 20A. This is what puts power to the N contacts on relay R201.

Maybe test the connector with a meter or test light, to make sure of what the truck is doign first, before jumping to using the trailer for a diagnostic tool

 

Use a volt meter at the connection point on the tow package so se if your getting voltage. Power is the center post I believe. If not the problem is at the fuse box. I had the same problem. Brake lights and signal worked but the lights wouldn't come on with the headlights. I just had to change out the fuse itself not the relay. It's a small little 10amp fuse if I remember correctly.

Hope that helps

 

Replaced that 20A and it solved everything. Thanks for the help.