Jimroll

Can anyone tell me if the 12v feed from the truck to the trailer is disconnected when the key is off? In other words, is there a possibility of the trailer house battery backfeeding into the truck If the 7 pin connector remains attached?

2018 F-150XLT 3.5 eco, max tow pkg.

thanks
Jim

ifallsron

From the internet: You'll need Single Park Light Diode (Roadmaster sells one) in order to eliminate back feed. To install the diode, you will need to severe the 12 volt hot lead from the deep cycle battery between the battery and 7-way connector. The diode will need to be placed on the trailer. There should be a set of instructions included with the kit.

Jimroll

Thank you.

PerryB

I'm almost certain the truck isolates itself from the trailer (when the key is off) via a relay. I can't speak with absolute certainty because I don't own a 13th gen, but Fords have been this way for about 20 years. You don't need to cut wires. I know the '05 and '13 in my signature both have relay controlled charging circuits.

Canuck_F150

my understanding with the smart connection Ford has put into the new F150s you can’t backfeed and drain the truck. this is part of the reason they went to the smart system.