Dirttracker18

FYI

you may want to check that with a multimeter or test light.

On my 04 there is constant voltage regardless of the ignition being on or not.

Same goes for my dads 09 Chevy, always on, he found that out the hard way during opening weekend for moose when he left his truck plugged in an had to use the furnace extensively. Woke up to a dead battery on the truck.

Most trucks I have worked on are wired this way.

Dirttracker18

This is a good idea, but normally reserved for a truck camper (slide in the box style) and not for TTs as they carry their own battery.

This could be adapted for TT use though.

Ron AKA

If you are worried about your battery going flat just carry jumper cables. I always use my truck battery to help out with the trailer load. In 25 years or so, I recall only having to use the jumpers once. It was in the middle of nowhere on a hunting trip and the temperature was -40 deg. Believe it or not, we boosted the truck with a ATV battery and got it started.

acadianbob

Ford is smart enough to have a relay that disconnects the "hot" wire when the ignition is off. Dodge/Chevy, maybe not so much. Be glad you have a Ford for many reasons.

PerryB

Beginning in 2005, Ford installed a relay in the trailer battery charge feed that is triggered by the ignition circuit so the key has to be in the run position for the trailer to receive power from the truck. Earlier Ford trucks have a battery charge feed that is hot all the time and will allow the trailer to draw down the truck battery. I'm almost certain that now all the major makers use an ignition driven relay to power up the trailer charge wire.

acadianbob

I had read that Dodge does not have this relay but perhaps others know for sure. Anyway, if you have a later model Ford, you are good to go.

Ron AKA

Yes, I suppose some safety regulation likely drove the change. For me I much prefer to have the trailer charge connection hot all the time so I can use the truck battery to help out with the trailer load. It is what allows me to camp for up to 2 weeks without moving the trailer or running the truck to charge the battery. Same deal with the cigarette lighter. On my old truck it is hot all the time. Don't smoke, but it is sure handy to plug in an inverter or charger so you can charge up the cell phone or other stuff overnight. When I get a new truck I will probably change the wiring to do the same.

cdru

Our 06 Dodge that we traded in on our 2014 f150 was hot all the time.I always unplugged so I would not run down the truck battery. That is why I asked the question originally. Thanks for all the information. cdru

raisin

My '99 Ford had the relay to shut off charge line with key off.

Billy bob

Storm Rider,

Any idea where your tech installed the fuse in the high power block. I just picked up a 2013 F150 screw w/ecoboost that the power terminal on my 7 pin plug does not have any juice going to it. I need it for my trailer battery. My 2008 F250 had it hot.