truck battery dead after parking with trailer hooked up

[sparc]

You are right, but this is only on the factory setups. Toyota and Nissan also did it right but GM took the cheap route and took out the relay. I have seen this more than one time.

Chris

Just to be clear for myself and my 2012 F-350, you are saying there is a relay that physically disconnects the power on all conductors in the trailer connection when thetruck ignition is off. Am iunderstanding you correctly?

Reason i ask is i'm not sure that's how mine works.

[Diamondpilot]

Just to be clear for myself and my 2012 F-350, you are saying there is a relay that physically disconnects the power on all conductors in the trailer connection when thetruck ignition is off. Am iunderstanding you correctly?

Reason i ask is i'm not sure that's how mine works.

Every late model Ford, say 1997 & on, has a relay for the 12v charge circuit only. Just this one function. All others are either connected all the time or controlled by the key switch.

The brake light works with application of the brake pedal, turn signals with its switch, reverse lights via the gear shift, running/tail lights via the light switch, ect.

Chris

[sparc]

That was my thought. If I want accessory power, I generally only want it to be on when the key is in the on or ACC position. Any alternative is just an invitation to run down one's battery. I will say that I have seen a few cars where they have one 12-volt receptacle that is keyed and one that is always on--perhaps if you are going to have some accessory that you want to charge up even when the car is off. I thought that was an okay idea, I guess.

I wish my ford had at least one of its four 12v sockets that switched off with the ignition, i have a dockingstation for my cell and it would be nice to be able to leave it plugged in and not have it powered up when i get out of the truck.

[Willl]

Went and poked around a little with a test light in the 7-way plug on my 2000 Dodge.

One terminal, approx in the 1 o'clock position is hot all the time, 24/7.

Lid on the plug has a pin layout and just calls it " + ".

[joshuabardwell]

Went and poked around a little with a test light in the 7-way plug on my 2000 Dodge.
One terminal, approx in the 1 o'clock position is hot all the time, 24/7.
Lid on the plug has a pin layout and just calls it " + ".

That's the 12-volt pin. You got it.

[RobertN]

Our older trucks do not have the relay. My Ram2500 is '01; the +12V "charge" line to the trailer connector is hot all the time.

Went and poked around a little with a test light in the 7-way plug on my 2000 Dodge.

One terminal, approx in the 1 o'clock position is hot all the time, 24/7.

Lid on the plug has a pin layout and just calls it " + ".

[Gary Fowler]

Yesterday I pulled the battery out of the box on the trailer. The box was about half full of water so I drilled some drain holes in the bottom while I was at the task. Used my multi-meter to check voltage and it was 12.39 v. I went ahead and put it on maintainer and will see what it does next time I am in my shop. By the way, the trailer had been unhooked for about 5 or 6 days and the battery was still up so, not sure why it drained the truck battery before. I will just unplug it from now on when I park it if I need to leave it hooked to the truck.

[Diamondpilot]

Yesterday I pulled the battery out of the box on the trailer. The box was about half full of water so I drilled some drain holes in the bottom while I was at the task. Used my multi-meter to check voltage and it was 12.39 v. I went ahead and put it on maintainer and will see what it does next time I am in my shop. By the way, the trailer had been unhooked for about 5 or 6 days and the battery was still up so, not sure why it drained the truck battery before. I will just unplug it from now on when I park it if I need to leave it hooked to the truck.

Sounds like the battery is fine. I would keep a eye on the trucks battery and charging system.

Chris