Are you using a good "7" pin adapter and not a 6 pin adapter? (next applies to my situation only) -- (U know they sell both and look identical. I use a "6" pin on my trailer, because trailer has no backup lights). If you have 12V at the proper pin, then it is a connector issue/trailer issue and not the truck. Easiest to check first.. BUY A new quality 7 pin connector and try that? If still no joy and you confirm you have 12V power, see diagram, then problem on the trailer side: (fuses somewhere, wiring, something). If you have things wired in, running in trailer, you need to check your fuse box and/or breaker panel in the trailer. heck, wiring from connector into box, could be bad, U just not know. You get to have fun troubleshooting, definitely watch some youtube videos, IMHO...
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See if U can check and see at panel in RV if power making it to trailer breaker box? Could be bad grounds, bad "trailer" battery, converter, all sorts of You tube Videos on all that stuff, thinking outside the box, but hard to Internet Guessnosis if not there.
OP, pulled this info from ETRAILER. You may want to confirm this also just in case:
What is the location for the fuse that charges the battery on my fifth wheel? Thank you
asked by:
Bill A
Expert Reply:
The fuse for the 12-volt accessory circuit feed to the 7-way is a 30 amp fuse in location F30 in the fuse box in the engine compartment.
Keep in min that due to the distance between the alternator on the tow vehicle from the trailer battery and the small wire gauge used in that circuit limit the amount of amperage that can be delivered on that circuit. You can maintain a battery but there won't be enough available amperage to charge a depleted trailer battery.
If shore power is available, you can use a battery charger like
# CTEK56353 to completely charge the battery. Another alternative would be to use a DC to DC battery charger like the Redarc
# RED46FR to completely charge the trailer battery using the tow vehicle's alternator as long as the vehicle is running
ADDED: On my 2019 1500 DT, I think that fuse is F01 on internal box, so U gotta look, if U want
