Trucks 7 pin harness

Anyone here ever haul a cargo trailer that has been wired to run lighting off the towing vehicles pigtail? Reason I ask is I’m curious if anyone has figured out yet how to get constant power when the truck is off. I’m not sure if a fuse is needed in the fuse box or if it’s like the third gen Tacoma and needs two wires
jumped/connected to get the constant power.

edit - my trailer is wired from factory and gets power for the lights from the trucks trailer connection. However it only works when truck is in the on position and it sure is a pain to leave truck in on position while unloading trailer for 10-15 minutes.

 

well, not sure if its much help to you

you could try swapping the wire on your trailer that powers your interior lights to the parking light circuit on the plug, then you could just leave your parking lights on when unloading, instead of the whole truck, but your interior lights would be on whenever the trucks lights are on, so you could add a switch in line to turn on/off when the trucks lights are on

the 7 way on the back of the truck does have a +12v Aux circuit, but from what your saying it doesn't sound like it supplies constant 12 unless ignition is on, as I'm guessing that's where your trailers interior lights are probably wired to

 

Based off this info here, https://www.tundras.com/threads/2022-tundra-fuse-box-locations-designations.105568/

“Bottom right” corner of the diagram of fuse panel 1 is the relay SUB BAT, that is the relay that switches the trailer charge / aux power with ignition. If you remove this relay and put a jumper across pins 30 and 87, that power will be on continually.

There’s a higher risk of ending up with a dead battery on the truck from this, but it will let you use your lights with the truck off. Another option would be an aux battery on the trailer, charged by the truck when it’s connected and running.

 

If you have the aux bed lights on each side of your bed over the rear wheels, you could get your power supply from there. Those can be switched on manually from the switch panel to the left of the steering wheel.

 

Does your trailer have a battery in it (usually needed if you have brakes and a break away switch)? If so, you can do a simple tap on the end of the connector to get your trailer lights to come on without the truck plugged in.

 

There is a battery but extremely small and only there for the break away switch. Doubt it would
Be a good idea to mess with that honestly.

 

Ty sir.

curious, you say higher chance of dead battery. Would that be because of the trailer hooked up to it or just anytime in general?

 

I can rewire from battery of the truck and use less power as then I’d at least only be using power from trucks battery to power trailer lights rather than trailer plus trucks cargo lights. It’s a viable option for someone wanting a factory switch though it’s not just something I’m wanting to do at this time.

 

Yeah, just a more room for human error by leaving the lights on in the trailer when parked, etc. Nothing that can’t be managed.

You will end up with more corrosion in the 7 pin connector too, the constantly energized pin will corrode faster than if it was switched power. You could always just pop the relay out and insert the jumper only when you need it, or keep the socket coated in dielectric grease to slow that down as much as possible.

Neither are a deal breaker IMHO.

 

Ty. Will try this out tomorrow

 

Don't want to hijack this thread... just curious about the power to those bed lights. With the switch in the ON position does it time out ? I would think yes to avoid draining the truck battery.

 

flipping the switch on or opening the tailgate, it has a 30 minute timer after which it will shut off if installed from the factory