My 1994 C180 Euro model is not cold enough when the a/c is on. The compressor/fan seems to switch on and off according to when I am accelerating or decelerating. A few months ago I put the thermometer on a stick thing into the air outlet and it showed something like -5degrees which seems to be cold enough at that time, but someone said it should have been colder like -10 or -15 inside the outlet. Now it seems to be warmer and the glass peephole on top of the drier/receiver in the engine bay looks dry. There is a crack in this glass peephole, but no wetness to show a leak. Does it show wetness when the gas is leaking? Normally there is a liquid in there which bubbles.