Just did this two minutes ago. Hope you have skinny arms!
Unplug the machine.
Remove the top cover by removing the three screws at the back
Look down and you'll see the unit in red.
You should be able to get your hand down to it.
Holding the unit and with the door open undo the two screws on the front of the machine where the door latch goes in - this will disconnect the unit.
Note the three positions of the wires connected to the unit and remove them by hand - just pull.
Connect the wires to the new unit in the same place.
Place the unit where the old one was and put the screws back in on the front.
Job done!
Ajare, February 2009