I looked at a few different prints, RV should be picked up. it comes from terminal 90 and 90 gets 24 volts as long as the 24 volt regulator on the relay board is good.
one of my prints shows RV n/0 contact feeding the hall interface board. it supplied 24 volts to what looks like a filter of some kind on the hall board. do you have any wiring diagram numbers on the controller, maybe i can get something close. i would really dig into the rv thing once again. or you can try just jumping out the n/o contact, as that would accomplish the same thing.