auxiliary cooling fans is always on

[Omran]

Hi every body,
I have a 1991, 190E, the aux fan start as soon as I start the car, for the last few months, I heard goes off just few times and then back on, it does not matter what temp is, some time it is freezing as I live in Canada and still the fan will go on, it is very noisy. How can I diagnose this problem, and what is involved for making the fan starts.
Here are some facts:
The Air condition is not working, I also get hot air from the side vents all the time, I will change the heater valve next week, hoping it will fix the hot air from the side vents.

I also had an issue with the cold start, and the OVP relay and the ABS light was on all the time, the fuse was burnt, I change the fuse and the car starts from the first click. Thanks for the advice.

Thanks in advance for your response.