I don't have a schematic for that one. But I would start with my DVOM and look for power across the contactor coil and work backward. water level safety, door safety, thermostat and pressure safety come to mind with a steamer.
The power supply goes directly from the the connection block to the contactor with the exception of a L1, L2 tap for control to the power switch. So if you un-power the machine and check the resistance with a ohm meter at the output side of the contactor, terminals 1 and 4 (the red 12 gauge and the Black 12 gauge wires) and then each one to ground. Then do the inner 14 gauge terminals. To ground should be infinite. If 0 ohms, one of the heaters has shorted. Each element should be about 20 ohms, or 8 ohms as a bundle.
I do have that diagram now. The high limit would not normally blow a fuse. Unless it got exposed to steam, water, or cleaning agents. But if you have power going into the high limit but not out, you may have found your problem.