2020 High Country 3500 HD will not power trailer jack motor or trailer interior lights

[Wahou]

Just got a new 3500 HD and unlike my last truck my powered Jack and interior lighting on my trailer don't work. How can I fix this? I assume it is either a fuse issue or the aux power is not connected, but I can't tell by looking.

[Another JR]

Do you have a volt meter?  If so check to see if you have 12 volts on pin 4 of the trailer connector. 

[Another JR]

Pin 4 is supplied by a 30 amp fuse on the battery. On a gas truck it comes from the aux battery if you have two batteries. If it’s a diesel i don’t know which battery it comes from. 
 

If your jack draws more than 30 amps you might have blown the fuse. It could also be an issue of connector pin assignments being different. 

Edited October 13, 2021 by Another JR
Typo

[shakenfake]

I suggest taking it to the dealer.

[Wahou]

Thanks Guys... I'm taking it to the dealer.

 

[unit]

Aren't those two things supposed to be powered off of the trailer battery?  Maybe you have something other than a travel trailer but any trailer with interior lights normally has it's own battery.

[Wahou]

Unfortunately, my other truck powered both. This is a horse trailer with a tack room. I used to could turn on the truck and the interior tack room and loading box lights would work, so it has to be something to do with the 12v battery connector, which I do not have.