aux elec cooling fans 92 500sl
 

hi, when should the aux fans run and how do you test them?????????/92 500sl

Mine come on at about 100 deg on the meter (way too high for my taste). I checked them by using the evaporator connector (I think I shorted it, off the unit), then the fans run in high speed continuously if all else is well. The evaporator is easy to get to, right behind the driver's headlight.

With A/C operation there should be 2 speeds & when the engine reaches 107C the fans also run at high speed.