while trying to unhook it, the wire leading into it broke off due to its being so brittle and worn after years of "cooking" in this hot engine compartment of my 450 SL!

so while it was broken I touched the bare end to ground with the ignition turned on and lo and behold the auxiliary fan cut on so I know I had found the right temp sensor.

so I am going to wire it directly to ground (lifting eye bolt nearby) and run the car with the aux fan running anytime the ignition is on to see if it makes a difference for me in terms of running engine temps. will update as I get data.

if it does make a difference then I'll investigate putting it inline with a switch instead of running all the time since it sure makes for more noise when the fan is running.

One question remains: anyone think that running the aux fan all the time will lead to its premature failure or should it be able to take on the load?


thanks again to all who replied.