It was solved by the Aux Temp sensor replacement.
What if the A/C doesn't work? I am not sure if it's low pressure or something else, but it hasn't worked since I got the car. I have other priorities so I haven't started it yet. The parts are a lot of $ too.
The Aux fan was coming on from the coolant temp sensor because that is what triggered the fan running and I replaced the temp sensor an it seems to be working fine.
I guess they can go bad.
'85 500SL Euro