Slide out and tongue power jack should be wired directly to trailer battery.....each would have their own power line AND in-line fuse.
There is also a 'main' fuse/circuit breaker on battery positive line..typically near/under trailer A-Frame before positive wire goes into trailer.
As for trailer tail lights...........those are feed from 'fused' circuit in trucks fuse panel. Check truck owners manual for position/location in fuse panel. It probably blew when umbilical cord was pinched/cut.
Same as trailer main battery fuse/cb
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31