I have an 04 F150, when I connect up my boat trailer, I have both turn signals and brake lights. What I do not have is running or tail lights. I checked the fuses, what I did find is that I don't have the R201 relay. Would this be the issue? Help!

 

Yes.

https://www.f150online.com/forums/to...locations.html

Post #20.

 

Ok, I found that it was a bad 20 amp fuse, replaced it and it blew as soon as I turned on my lights. What should I look at next?

 

Which exact 20 amp fuse?

 

The one that is located in spot #10.

 

You should be looking for the short circuit.