I bought a 97 Mercedes c230 back in December. Now that it's summer time I tried to use the a/c, but when I turn on the a/c only hot air blows out. When I set it to cold then fan speed also varies on its own, it'll blow hard for a minute and then tone way down and just blow air softly for a few minutes. I bought some r134a with a gauge assembly, and when I put the nozzle on to check the pressure it goes into the red on the gauge after a few seconds. Which the gauge says Red = Hardware Problem..

I'm not sure what to do about this, and any help / information is very much appreciated.

 

have you checked to see if compressor is kicking on ?