I assume the fuse you mean is the one thats attached directly to the control itself, white ,small square with a thermal link attached to it. This should be checked for continuity. Very common failure and they have a redesigned kit which splices the bad terminals going to the fuse and has new ones, another cause for opening the thermal fuse is loose wire nuts at the junction box causing excess current flow.
If this checks good, check power supply going to the fuse (two black wires) and also the black whites at the door switch for 115 volts ac

On checking the fuse its more important to check continuity then voltage, Do you know how to check this?, assume you have a piece of wire if you went from one end to the other it would be 0 ohms or no resistence if the wire was damaged or broken you would show no continuity or O.L on a digital meter for outer limits.
when you said you checked the door switch you have two black and two white going to "microswitches", two black have 115 volts the two white's are neutral and won't show any volts. Check black to white or black to ground, also you can check continuity of those micro switches (WITH POWER OFF) by pressing the tabs down with a small screwdriver.