Double_J

I've mentioned it before in this thread, but have you checked the connection on the back of the trailer wiring connection on your truck. Literally crawl under the rear and find where the wiring harness plugs into the sockets at the bumper and make sure its connected. I had the same problem and the main wiring harness was just hanging there. It only plugs in one way and has an audible and tactile click when it's locked in place. It's worth the 30 seconds it takes to at least check it out.

jasonginn

Thanks man.. Yeah I connected my trailer and sat there for probably 15 minutes and nothing ever said "trailer connected". I text the local ford service manager and he said for me to bring the truck back and they can look and see about that "smart trailer connect" and see if it is enabled.. so this will be the 7th or 8th trip back to a dealer..

jd50i

I couldn't get the video off of my iphone last night and IT has my work computer limited on what it can do.
Before accepting the truck back, have them either connect a trailer or a tester to show you it is working, don't accept the truck back until they can show you everything is good.

jasonginn

Well they tell me that the test light shows power to the plug, but I dont think it is sending the right power or since the computer doesn't know a trailer is connected it doesn't work. I have put my multimeter on it before, but it was very low voltage on the RS and LS which is the right signal and left signal.

Beo-Chin

My last few trucks came with a relay in the glove-compartment that has to be installed into the fuse box for the trailer lights to work. Come to think of it, i haven't noticed a relay laying in my 2018's glove compartment......

jasonginn

Yeah I know the older models had to have that relay installed.. I think that stopped at the 2015..

jd50i

I did not have to install anything.

jasonginn

Well, I took my truck back to the 2nd dealer yesterday for the 3rd time and they checked the computer and said there is no "Smart trailer connect" in the computer to enabled.. He said they are going to try again today to see if they can figure anything out..

jasonginn

Well fellas they fixed it.

All they did was take every connection apart and clean it. From front to back that had something to do with lights.

I have trailer lights now.

Thanks for everyone that replied.

Jason

Wanda Woods

I have had this issue with a 2015, 2016, and 2018 and Ford is no help. Have rewired the trailer twice and still doesn't work. Have also tested the trailer wiring and it works. Truck will not read that there is a trailer attached