Not sure if you guys have covered the rad fan switch or not but I made some discoveries today and thought I would share. The switch on my XCW failed after the first week, so I called the dealer and was told I was SOL but I could get a new one for $54
As fate would have it, my 390 Berg switch was also bad and they happen to be the same. An 84 BMW 318i switch will work and they're offered in 91c and 99c but nobody local has them....of course.
I decided to paw through a friends parts bin at a rally shop and see what I could come up with but found nothing that would work. We decided to chuck the switch into the lathe and pop the cap off and have a look inside. The reason why the switch failed was burned out terminals, the bi-metal disc and popper was fine. My theory is that the switch isn't rugged enough to pass the current for the fan and burns out prematurely. I think the solution is to add a simple relay to the circuit and run a pair of leeds to the fan from the battery directly, with a fuse of course.
The cars that use this style of fan switch all have a relay, so it's obvious to me that it's a start. Probably better for the fan also, since it's not pulling so much amperage through the fan switch. Anyway, there it is