1999 Mercedes Benz ML430

Air Conditioning problem
1999 Mercedes Benz ML430 V8 All Wheel Drive Automatic 142000 miles

ac blows cold but will turn to hot, turned the switch on and off and it will blow cold again. Thinking it might be low on freeon put or held almost a pound, still did it but not as much maybe once all day, after about 4 days it doing it 4-5 times a day again. Seems light maybe a small leak and something electrical, do you think it might be a low pressure switch
July 22, 2009.

Yes, it does sound like a slow leak.
Do you have a set of gauges so you can see what teh actual pressures are?

Jul 22, 2009.