Should I just pull fuse on leveling system and use bars to level?
I have two tow vehicles with this type of setup from the factory. You should find VERY specific directions in the owner's manual regarding setting up the load equalizing hitch if the vehicle has the appropriate trailer tow ratings. Each one of my vehicles has a different procedure. One calls for loading the tow vehicle ready to tow, then getting it aligned ready to hitch and turning the ignitition off so that the automatic level feature doesn't try to further inflate the shocks - - then hitch and adjust the weight distribution bars before re-starting the tow vehicle. The other calls for inflating the air springs to 30 psi then following the setup instructions just as with the first vehicle.
Disabling the system by pulling the fuse with either of my vehicles would result in the potential for serious (EXPENSIVE) damage to the automatic leveling system. I will admit that both of my vehicles are older - - a 1975 Cadillac Eldorado and a 1985 Oldsmobile Delta 88 Royale Brougham Luxury Sedan - - so they may be a bit different than the current crop of vehicles with automatic leveling systems.
Good luck with your tow vehicle adjustments.