I have a 1991 Mercedes Benz 190E that is new to me, this is myfirst Mercedes. When I turn on the A/C all I have is hot air. Any ideas as to what could be causing this?

Also, there is a red button in my center console that doesn't do anything. What is it and what should it be doing? Any help would be greatly appreciated, I don't want to go to a mechanic and get swindled. Thanks!

 

Go to mbworld.org or benzworld.org much bigger data base for you to get info on the classic,could be low on freon,also someone will have the info you need on the button,Do you have a manual?someone will look it up for you if you dont have one.
ohlord
"GOT CODES?"

 

Is it hot air or just not cool? Make sure the a/c compressor is engaging and the freon level is up to spec. If the compressor appears to be ok, look at the heater valve. I can't remember if it has a monovalve or duovalve. Use a pair of hose clamp-off pliers and pinch off the heater core/heater valve inlet hose and see if the temperature gets noticeably cooler. If a/c cools as expected, the heater valve is faulty and allowing coolant to bypass into the heater core and fight the a/c from cooling.