No +12V on 7 way plug.

[EJH]

I have a 2019 Lariat and wanted to figure out a way to have the 12V Charge circuit [Pin 4] light up without a trailer connected (my camper has a battery I want to keep charged).
It turns out a 1A 12V lamp on the LT and Stop Lite connection [pin 5] will 'trick' the TRM into turning on the 12V charge line.
The truck needs to be running and in gear for the charge circuit to stay energized. Putting the truck in Park deactivates it but it turns back on in Drive. Perfect.
It may work with a lighter load, I have not tried.

Another option instead of tricking the 7-pin into providing the 12V supply is to use the bedside 12V outlet (driver's side). See this thread.

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[Geoff]

Another option instead of tricking the 7-pin into providing the 12V supply is to use the bedside 12V outlet (driver's side). See this thread.

Yeah, I saw that and I know where that connector is. But I'm planning to get a Scout YoHo [truck bed] camper and it uses the 7 pin plug. And I like the way it turns off if not in gear. Makes for a more 'fool proof' setup and keeps my ride battery ready to go..

 

[EJH]

Yeah, I saw that and I know where that connector is. But I'm planning to get a Scout YoHo [truck bed] camper and it uses the 7 pin plug. And I like the way it turns off if not in gear. Makes for a more 'fool proof' setup and keeps my ride battery ready to go..

I've seen the Scouts locally on Rangers. They are nice.

 

[Geoff]

I experimented some more and discovered a simple 4 conductor trailer wiring checker plugged into the 4 pin connector socket lights up the "Trailer connected" message and subsequently turns on 12V at pin 4 of the 7 Pin connector.
Given this is it's clear it does not take much current on either the LT or RT pins for the trailer module to sense a trailer. It does not seem to monitor tail light current.
I'll probably choose to put a simple resistor on the RT and LT lines [at the pigtail end of the 7 pin cable] when I get my camper to keep the truck happy and the camper charged.

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