Looks like you have an LED light on the trailer. There are posts on another thread talking about getting errors on the truck when the trailer has LED lights. Might be the same issue.I added a resistor to the the airstream right tail lamp and no longer get the error. All fixed I guess.
BTW - At first didn’t work...thought it was odd no heat coming from resistor and was still getting error...used multimeter to confirm wiring and what do you know airstream used wrong wire. Once I connected to correct wire the resistor got hot and error went away.
I have a similar issue. After repeatedly getting the fault message, I realized the trailer faulted whenever the truck lights were turned on. If the truck lights are off, the trailer lights work perfectly. I’ve had the truck less than a month. It’s a 2021. Ford says it’s a trailer issue, but the trailer works fine with a 2019 vehicle.I just traded my 18 F150 super crew in last week for the 21 version. I’m having an odd trailer light issue as well, wondering if anyone had any insight.
I hauled my galvanized dump trailer to a job site Monday morning with my 18. No issues as usual.This trailer isn’t quite a year old yet, and I’ve never had a problem. Traded the truck Monday afternoon, and when I hooked onto the dump trailer with the 21 Tuesday morning, checked the lights and all was good. Headed down the road and got the “trailer light module fault” warning. I pulled over, checked the lights again, everything seemed to work so I continued on. The warning continued to pop up every 20 seconds or so. I’d hit ok, clear it and it would come back. Luckily I didn’t have far to go. When I got back to the site, I got one of my guys to help me check. When I hooked up and checked the lights, all was good. As soon as I pull the truck in gear, I lose both signal lights and brake lights. Back in park, they work. Also, as soon as I shift out of park, the trailer marker lights come on. This is my sixth F150 since 07, and I’ve never had one do that before. And yes, since it’s a new truck I took it back to the dealer, but so far they’ve got nothing. The “tech network” says it must be trailer related, and that would make sense because my 13 year old enclosed cargo trailer works no problem. It just doesn’t add up to me because my 18 had no problems, and I took both the truck and trailer to the dealer and they tried a 19 they had there and it worked fine. But another 21 they had on the lot did the same thing as mine. It doesn’t make many sense to me at all. Any thoughts? Side note, one of my guys hooked his 18 GMC up last week just to see, and the trailer lights worked fine.
This could be super helpful to me. My boat trailer is a 2020 model with all LED lights. I've had intermittent issues with the right turn, then left turn signal fault. Yesterday was most frustrating as driving down the freeway, after nearly 140 miles of towing, getting both turn signal errors, I got "trailer disconnected" error. A few miles later, pulled in to a park and ride to check, and, of course, all lights were completely fine. I didn't even disconnect and reconnect, just had my son verify by inspection as I tested all the functions. After verifying, I did disconnect/reconnect to make sure the truck had a chance to resync. So annoying. To top it off, backing the trailer in the drive way to park it, my reverse sensing was all messed up. Even though I was in tow mode, had an active trailer selected, when I was backing up, the rear proximity measure was blaring away convinced I was going to hit the trailer. I even stopped and re-started the truck to no avail. I'm going to try one of these to see if it doesn't address the issue. The truck pulls the trailer so well, and I couldn't be happier. But, yesterday, I was so frustrated with the electronics side of it.
Did you ever get a fix for your issue?? I am having the same issue and also getting Trailer light module fault and my alarm keeps going off saying trailer disconnected if I leave any of my trailers connected. It’s going to the dealer next week. I have changed adapters, have 3 trailers of my own plus towed someone else’s and they all do the same thing. Really pissing me off that a brand new truck can’t tow a trailer without setting off alerts and r the alarm at all hours of the day or night.Hey guys - just setting up my new Lariat PB to tow my Airstream...everything was good until I got this message. I checked all the Trailer turn signals and they both work fine when Im hooked up. Power to my Airstream's BT rear camera, trailer brakes, side marker lights and as mentioned the turn signal lamps. The truck recognized that the trailer was connected and did al the enabling/disabling of the different systems.
The message keeps coming up even after I acknowledge it by hitting OK. Sometimes it goes away sometime I have to hit the OK. Also took a picture of the plug on the F150 and the the 7-way from the Airstream. I am going to look up the 7 way plug diagram and see if there is something off...but everything works. Anybody have an idea?
I also have the same trailer light module fault issue with my 2021. I tow four different late model trailers and all have this same problem. The lights on these trailers worked perfectly with my 2016 F150. The dealer has already replaced the tailer light module (two days in the shop) but that did not fix the problem. In my case it is not a trailer issue.
