Replacing the power module is quite the chore as there aren't any videos out there that show the whole procedure. I'll highlight the steps to do this so it won't be a frustrating experience. Use tape to mark wires and their connectors so it's easier to reassemble. Take pictures so you can reassemble easier.
Tip the mower up and remove the blade, the bolt comes out with a counterclockwise rotation, and put the washer and bolt back on so you don't misplace it.
Put the mower back down and remove the rear black shroud, it has 6 screws. There are 4 connectors and you need to cut the red wire 1 1/2" away from the safety relay. This wire will need to be soldered back on. I covered the connection with heat shrink tubing when I reassembled the unit.
Remove 4 silver bolts from the bottom of the mower deck and lift the whole shroud unit off the mower, it's heavy.
Remove the single screw from the push button panel for the lights and lift it off. Remove the small E clip on the metal shaft and use a punch to push out the shaft towards the end that had the E clip. Lift off the clear battery cover and set it aside. Unplug the yellow connector from the controller to the motor and cut the silver tape to remove the thermocouple.
Remove 5 screws in the top cover, remove the cover and set aside.
Remove the 5 screws on the bottom of the shroud and then separate the shroud from the motor. You'll have to cut a zip tie that holds the white resistor to the motor before you will be able to remove the shroud completely.
Clip the zip tie that holds the wires near the rear of the shroud.
Remove the screw and washer that holds the power module on and lift the board out. Remove the fuse circuit board from the plastic holder in the shroud.
Remove 4 screws that hold the battery connection and green battery release button. Remove the green button and spring from the small assembly. Then you can lift and twist the battery connector out of the assembly.
Reverse to assemble.
Fun is.