Are you sure it's the thermal switch ??? This switch puts
ground on the fan relays so you might want to take the wire off and ground it to the frame and see if the fans come on. Nine times out of ten it's the fan relay that has gone south but if you do need to replace the thermal switch
it's best to drop the radiater down from the bottom so you can see what you are dealing with. I once saw some pictures of Bill W and another guy Wes changing transmission
oil and it still cracks me up today....
McDoo former owner of 931