Just wanted to get a post into the archives for anyone searching for
radiator fan thermoswitch information. I hadn't noticed any recommendations
about testing the switch before putting it in...and just made that mistake
myself. The recommendations are probably there...but difficult to sort
through.

I just had a brand-new thermoswitch that does not make a connection at any
temp (room temp up to 100 C). Save yourself some time, test it first with
either method below: I always test thermostats before putting them...don't
know why I didn't think to test the thermoswitch???

1. (MAKE SURE YOUR FAN AND ALL WIRING IS WORKING FIRST - plenty in the
archives for this, and a great write up on vanagain.com)

2. OPTION A: Use an ohm meter connected to the center and one of the outside
terminals (check both, but only one will work, mine is the one on the left
of the switch if the notch is on the bottom). Place the end of switch in
water at the proper opening temperature- should read 0 resistance at opening
temperature and beyond for the low speed. You can check the high speed by
connecting the ohm meter on the two outer terminals and raising the temp of
the water to the opening temp for high speed operation.

3. OPTION B: Hook the new one thermoswitch to your fan (do not put into
radiator yet, leave old one in) and place the end of switch in water at the
proper opening temperature (just like the method above). Your fan should
come on when the switch reaches temp. Keep in mind, there is a range of
opening temps - check the info on the switch you bought.

Ben
'88 Wolfsburg Weekender ej22 "Angry Anker"