At what temperature are the auxilliary fans supposed to come on in a '95 C280? Mine never seem to come on, even at temperatures close to 110. The do come on when the A/C is on, but only for very short durations. I don't have access to wiring diagrams or any other shop information and would like to know where I could tap in a parallel circuit to run the fans manually when desired. Also, what controls the fan relay, is it the temperature sending unit or something else. Thank you.