1991 190E 2.6 Auxiliary fan is always on
 

After searching the forums for info on this problem I found useful info that has helped understand they work but my problem is the auxiliary fans are always on, doesnt matter if the car is hot or cold they are always on. I have looked at some tested out the relays which the govern the fans and they checked out ok.
Where else do I look and/or links should I read to solve this problem??

Which fan is always on??

The 2 small auxiliary fans in front of the radiator are always and doesn't matter whether the car is up to normal operating temp whether after the car has been started up.

Again I ask, which fans ? High speed or Low speed fans
Your car has two different fan circuits ..HIGH/LOW..they are completely independent of one another and if you can tell me which speed is always ON, that will cut my disgnosis time in half. I don't want to be telling you to check the low fan high pressure sw if , in fact, you have a high fan, which would indicate a completely different switch/circuit.

so, which circuit are we looking at ?? High Fan or Low Fan ???

I have the same problem. Mine is low speed.

Both the high and low are on at the same time wether its a cold or hot engine.
:confused:
Seems to me like they should turn a certain temperature and not be on all the time according to my understanding of they work.

Oh. we have a Twofer..

Unplug the high pressure switch at the reciever/drier [ the one with the pigtail wire leads] ..see if low fan stops..

Your understanding is in error.
They work in unison and they are both on LOW or HIGH. There is not a seperate fan for low and one for high..they both are turning high or low, at the same time.. the speed is determined by which circuit is feeding the fans at that time..if it is a high fan, it is the engine coolant temp circuit..if it is a low fan speed , it is the /ac control circuit feeding the fans
So............
The SPEED is the first question.
If you are insure which speed , then unplugged the relays you say you have tested ..[ one at a time] ..one relay is for low speed and one is for high ..When you unplug the one that stops the fan, you will then know which fan speed circuit we have a problem on. The we can do the next test step.