Hey guys....quick-ish question......

I have a 2019 STX F150. I tow a 6x10 enclosed trailer frequently in the summer months. The trailer was originally a flat 4 pin connector. The trailer has 2 LED lights inside. I’m having my trailer shop convert the flat 4 to a 7 pin round connector. The idea is to have my interior lights operate while hooked up, but not with truck and/or lights on.

Trailer shop said only issue is Ford may not have included a wire/fuse/relay to enable the correct wire to have power.

I seem to remember reading something similar awhile back, but now don’t remember and can’t find it. So....is there a way to tell by looking at a fuse box if my ‘19 is already equipped, or if I need to get to the dealer? Trailer wiring should be done this weekend so I’d like to have the truck ready to go.

Thanks!

 

I can't directly answer your question about a 2019 but this sounds like your trailer guy is blowing smoke. If your truck has the Ford 7 pin harness you have the Aux. power wire already that is separate from your headlights. You will probably have to add a switch for turning the interior lights on and off or an open door switch where the lights will come on with an open door.

 

Huh. Ok. The trailer guy mentioned some about a wire or a fuse dealing with charging RV batteries. I just found a diagram of the power distribution box in 2019’s.....fuse #30 is labeled as trailer tow battery charge, so that sounds like what he’s talking about. I’ll just have to check the truck when I get home. Not sure if it’s installed or not.

 

I could be wrong about this but I've never seen a Ford truck that came with a class three hitch not also have a seven pin connector. Do you have a class three hitch? Same goes for a factory installed trailer brake since they require a seven pin connector. You might also want to look at etrailer.com . They have a lot of harness info on the site and you may find what you need there.

EDIT: Adding a switch is just so the interior lights aren't on all the time. AUX power may or may not be ignition switched also. My experience is that it usually is.

About the trailer battery. I've owned a number of camping trailers and everyone had an AC\DC power distribution panel that controlled the charging of the trailer battery. While running, truck power went to the panel which is fused\breakered. The panel controls how much charging the battery needs, not the truck.

 

My STX has the $995 trailer tow option, with 4 and 7 pin connectors. No trailer brake. Not sure what hitch is factory. I think the question from the trailer guy is getting power to thru the 7 pin at all times, without the truck or lights on. According to him, some vehicles are ready to go, and some require an extra fuse potentially.

 

A quick google search says Aux power comes already fused. Class three is the receiver hitch under the bumper that is bolted to the frame.

 

I also have a '19 Truck needs to be on for power to the battery circuit. Reason being if your camping and leave the trailer connected you'd drain down both trailer's battery and truck's given enough time and current draw if the truck didn't disconnect the feed when the truck is off. Put a small battery on the trailer tongue to power the inside lights, snowmobile trailers use them all the time to power the electric brakes if there is a breakaway.

 

Well, shoot. Kinda defeats my purpose then. I don’t have room for a battery up front with the v nose and jack. Honestly, that’s more than I need anyways. I was just trying to come up with a way that the truck didn’t need to be turned on, with the lights on, to power 2 small interior LED lights.

I suppose though, that maybe the 7 pin gives me power with the truck running, but I can at least have the lights off.

 

My buddies V nose snowmobile trailer has the battery inside, tight in the V. maybe that could work for you

 

I wouldn't recommend it but it's easy enough to disconnect the Aux power from ignition switching. Also the truck doesn't need to be running to have power to the trailer lights. The key just needs to be in the accessory position.