When I connect the flat four connector from my boat trailer to the truck, everything works except for the running lights (turn signals/brake lights work fine). It is not the trailer because I hooked up to another vehicle and everything works. Anyone have an idea? I thought fuse? I checked the fuse in position 10 under the dash and it is fine. I looked at the relays under the hood, there is no relay in R201? Could that be it? Please chime in with any ideas. Thanks in advance!!!

 

The owners manual I'm looking at says there is a R201 half relay in the passenger compartment panel which is for the trailer park lights. If that one is missing that would be your problem.

It also shows an R201 under the hood for Daytime running lights. If you don't have DRL's then it would probably be missing there but shouldn't be needed anyways.

Make sure you're looking in the correct location.

 

If your truck came with the "towing package" there should be a plastic bag with that relay and a wiring harness for a brake controller(I think). Just plug that relay in and you'll be good to go. If not, you'll need to pick up the relay from and auto parts store or the dealership.

Check the glove box, center console, or behind the seat for the bag that contains the relay.

Good luck.

Joey