I thought I'd post this in case it might help somebody :spongebob -Check for controller failure first. Remove vent housing on top of main plastic housing- push in on sides and pull up. Remove main housing. Two bolts are underneath the vent housing and there is one at the bottom of the compartment on the left under a round cover with a screwdriver slot- turn left 1/4 and pull cover out to get to the bolt. Remove seat, pedestal and ducting. Seat has 4 allen bolts in the front and the back of the rails. I had to unbolt the fuse block bracket to get the seat back far enough to get to the front two allen bolts. If you're by yourself its easier to roll the seat out over the sticks and through the front window. Remove the brackets and misc bolts holding the cover where the computer sits and gentle move the whole mess towards you to get at the motor hosing. I took the duct off the motor housing because it makes it a little easier to get to the mounting bolts and it makes unplugging the duct easier. Now is a good time to clean the filters
I know your pain Rob, been in the cab of a number of excavators, hard on my old knees nowdays. I typically lift and stow the front upper glass, remove the front lower glass, and on most machines the drive sticks are attached to the drive pedals with bolts, so I remove the sticks and get them out of the way, really opens up cab area getting seat out and working inside cab. Once I get the seat out, and everything opened up, I place a small floor fan just behind the pedals, blowing out, stand outside the door on the track, and unload on the inside of the cab with compressed air blowing all the crap and dust out of there. While you're in there and got the fan housing out, be sure and check the evaporator core that it's not clogged with dirt.
I have a 120 C JD and my fuse is blowing for the heater fan, by your pics it looks like the same set up