The fuses are on the control box
which is behind the dash on the early coaches. Pull the panel away that is in front of the passenger seat and then remove the cover on the left that is over the fan unit. The control box is on the floor and you should be able to pull it out far enough to check the fuses.
Does the generator slide work? This uses the HWH hydraulic pump and solenoids but bypasses the control box so that may help to narrow the problem down. If the slide does not work there are other fuses inline with the pump in the small compartment behind the passenger front wheel.