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Old 04-25-2020, 04:24 AM
Usaguy Usaguy is offline
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Join Date: Aug 2019
Posts: 949
Quote:
Originally Posted by Jorn View Post
Noticed that the aux fans of my 1990 300SE turn on when the engine is at normal operating temperature of 80*C with no AC. This happened in the last three days, any suggestions of what could cause this? Now that I think of it, it started doing this after I ran the AC for the first time since the summer.

Do they come on at high fan speed or low fan speed?


if at low speed then check the switch on the a/c receiver drier (when it's closed the fans run, there are 2 sensors only one does fans)


if at high speed then check the sensor on the cylinder head
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