2018 350 with utility body. (39,000 miles)

I pull a trailer for work once or twice a month. Problem started within the first 1000 miles. Dealer said not their issue because I have a utility bed to replace the stock bed.

The dash works great when the trailer is plugged in. But with no trailer I get the warning ping that the trailer is disconnected when I apply the breaks. It then will ping that trailer is connected when I let off the break. I occasionally get the added bonus of the ping for left trailer turn signal fault followed by the ping for the right turn signal. I tried the manual trailer break switch and that didn't seem to set it off.

This was a problem early ( first 1000 miles) and want away for a while when I started plugging in and unplugging with the truck off and the lights off. I drove across country with trailer and had nine months of no issue in Ca. Winter in Maine is what seems to be the trigger. Got the truck in December of 18 in Maine. I was in ca for winter of 19 and had no problem. The gremlin is back for the Maine winter of 20/21.

 

You may have damaged the wiring and/or the trailer plug when you changed out the bed for the utility trailer. I would look at the wiring and double check where the trailer adapter plugs into the truck's wiring harness. Also I would use dielectric grease in each connector. You may have some moisture getting in. If I remember correctly, Maine gets snow during the winter and uses salt to clear roads. It may be working into the connectors. I would also use dielectric grease on the truck's trailer connector and the trailer plug itself. Cut down on moisture and corrosion. California is pretty dry normally and a moisture issue might not occur. Also check both ends of the truck trailer connector (trailer plug and at the truck wiring harness) for any corrosion, moisture or dirt on the pins and for exposed wire where the connector plug receives the wires.

The dealer is assuming any changes you made to the bed was owner caused problems. Broken wires, bad plugs, moisture can be written off as owner caused.

 

Thank you for the quick response. I will pull the beast into the shop for a dry off and a warm up and check that out.

 

24 hour fix. 23 hours thawing out one hour to find bad splice and fix. Thanks.

 

Man that Maine winter....surprised anything works!

 

THANKS for reporting back on the fix! Thank you.