1stTruckGuy

I was finishing prepping my tent trailer for camping season today (lights, wheel bearings, propane, battery check, etc...) and thought I'd check the factory tow package on the truck as well. I have the factory tow package, and know the lights work on the trailer because I towed it across town the other day. Well today I also installed a brake controller to run the trailer electric brakes which I have not had a chance to test out yet. Some googling today, and I came across this diagram:

http://www.f150online.com/forums/tow...cations-2.html

I have all the fuses installed EXCEPT relay #5. Do I need it? My trailer does have a battery on the tongue, but I'm not sure if the inverter in the trailer is setup to charge it or not off the truck. Common sense would dictate that since I have all of the other required fuses in place, that my brake controller will operate the trailer brakes, but by not having relay #5 I just can't charge the battery in the trailer while driving? Does this also mean that I will have no power to the trailer from the tow vehicle (overhead lights inside the trailer) when hooked up? Or for example, that I can't run my 3 way fridge in electric mode while being towed to my destination without this relay?

I don't tow often, would it be detrimental to buy the relay and leave it installed even though I'm not towing much? Makes no sense why ford would not have just pre-installed this fuse. I know they came in the glovebox with the pigtail for brake controller but I am not the original owner and didn't get that item when I bought it used.

GATORB8

Relay 5 provides power to the power pin of the trailer connector when the truck is running. Should be pretty cheap, I'd just bite the bullet and throw it in.

techrep

iTrader: (1)

My truck came with that relay with the tow package wiring...and the inverter does not charge your trailer battery...it inverts DC to AC power...

1stTruckGuy

I guess the better question I need to figure out is how I would know if my trailer battery is setup to charge from the truck, or is it just going to work that way by nature of being plugged in. I assume my trailer brakes will still function without this relay since I have the proper fuses installed for that?

murf

All campers come ready to charge off of your truck. (unless someone messed with the camper wiring. ALSO ONLY if you have a 7 pin adapter) If you have a pop up with a 4 pin adapter your battery will not charge no matter what. Without that relay you will not charge your camper battery.

And yes your brakes will work fine without it.

Relays are like $6

You can test your battery with volt meter. Without the truck plugged in it should read 12ish or less, plugged in it should jump to 14ish

Some people, like myself, jump that relay to give that wire (orange) power without the key, to put lights in the bed. I have a switch in my bed to turn on light in my bed. Makes it much nicer hunting when I can see my stuff in the morning

1stTruckGuy

I stopped at a local junk yard today at lunch and told them I wanted this relay. They said go take a look in the yard. I pulled 3 of them just in case I needed a spare. Best part is they told me to take them, free of charge. Sure beats the 15 bucks each auto zone wanted.

techrep

iTrader: (1)

Nice....I like Free

4x4angel

relay # 5 is use for electric brakes . with 7 pin plug and charge the camper battery. without it ,only tail/brakes/turn lights will work.

bubbabud

Wrong. With the relay and fuse installed it will provide ignition on power to the 7 pin plug if the camper is wired correctly it will charge the trailer battery. I like some others just put a jumper in place of the relay so the plug is hot even with the ignition off

4x4angel

i forgot about the the damn fuse. and then i got confuse .lol