GlennRMK

What do you need to do to make the interior lights work on my enclosed trailer?

Hooked my buddies Chevy to my trailer and the interior lights work.

Hook the trailer to my 2011 F150 and they don't work.

Whats the procedure?

changexlt

You might need to have your vehicle running to get power to those lights. If that doesn't work, check your trailer tow charging circuit, fuse and relay and still have the vehicle running. Dad's 03 F150 needs it running and lights on, for the featherlite stock trailer's interior light to work.

Abn150

More than likely, the interior lights are set up to run from the constant power aka battery charge circuit in the trailer power cable.

In order for this circuit to be active, there needs to be a relay in position 9 (TT battery charge relay) and a fuse in position 21 (TT battery charge fuse) in the power distribution box in the engine compartment.

This relay and fuse should have been in a plastic bag in the glove box or somewhere else in the truck when you bought it. Unless the dealer installed them for you, they do not come from the factory installed.

Check these two positions in the fuse box, if they are empty, that is most likely your problem.

smokeywren

On my 7'x14' CarMate enclosed cargo trailer with interior lights, the trailer wiring must be plugged into the truck, and the truck lights must be on. Plus the light switch in the trailer must be turned on.

If your light fixture has a switch on the fixture as well as being controlled by a wall switch, both those switches must be on.

For most trailers, if the running lights work and are turned on, then the interior light(s) should also work.

But on some trailers, the interior lights are powered by the battery-charge wire (12-volt hot wire) in the 6-pin or 7-pin wiring plug. In that case you don't need to have the trailer running lights on for the interior lights to work. Since most cargo trailers don't have a battery in the trailer, some trailer wiring connection techs don't even connect the hot wire inside the plug, so it's never "hot". And some tow vehicles require additional parts (usually a relay) before the 12-volt hot wire will work.

So use a test light and be sure the 12-volt hot wire is hot.

Here is a link to a typical 7-pin trailer connector. Notice the black wire is usually the battery charge wire, and it may also be called the 12V wire or the hot wire.
http://www.drawtite.com/6and7waywidi.html

Bottom Dollah

Mine was in the bag and I bet you're right about the problem.

Macken37

I had large enclosed trailer on my truck before. I do have the brake controller and the fuse and relay installed needed. The only way I could get my lights to work inside the trailer its to have my truck key in and on the on position. 2010 f150

hihocarp

What I did on my 12' enclosed as mount a battery box on the hitch, wire the interior light to it & then ran the charging wire to the battery from the truck. The wire was already in the hitch powering the light so it was just a simple splice into it to charge the battery. Otherwise I had to have the truck running to power the lights.

smokeywren

Makes sense. Otherwise some idiot could leave the lights on in the trailer and run the truck battery down.

terroraz

Thanks this was exactly my problem. Found the relay and fuse in a sealed plastic bag located inside the cab. Installed them on position 9&21 et voila all fixed. Thank a million.

WXman

This forum rocks. I would have had no idea that I needed to add a fuse and relay under the hood to get all the functions of my trailer to work. Who would have thought that a towing package wouldn't come with everything you need to tow? I ordered the stuff online and my trailer lights now work like a charm!