When should the Cooling Fans on an '89 190E 2.6 activate?

The reason I ask is that mine never seem to be on. The temperature gauge usually shows around 80C(176F). If I'm stopped for an extended period of time such as a drive thru, the gauge almost reaches 100C(212F).

Frank
The AUX fan only come on when engine temp gos
110c (high speed) or air condition is on (freon pressur over 250psi)low speed.
AUX fan has two speed!
Hope this Help!


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MB STARS Master Guild Technician,12 years MB tech
5 years independent shop owner

The system has a relay and a pre-resistor for the 2 fan speeds, as I understand it (my 95' S320 is set up this way)

Mine comes on at about 90 degrees centigrade (slow speed) and 110 degrees centigrade (high speed fan)

There is a temperature sensor that sends info to the AUX FANS circuit to turn them on/off through the switching relay. The A/C head pressure will also turn them on. On my 95', they had to replace the pre-resistors, as only 1 fan speed would come on (high, but not low)