I think 12V power to the slides comes directly from the house batteries, mine does. The positive cable goes to a circuit breaker, then on towards the slide motors. This circuit breaker should have a tiny re-set button on one side/end. Usually it is hidden by something. I had to use a flashlight and mechanics mirror to find its location.
If that is not the problem, I suggest using a 12V test probe, beginning at the battery and working along the wiring untill you find the dead spot.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"