demosc430

Hey everyone, my name is Ron, im new here and i need some help with my mother's 1995 s420... the AC is only working when the car is idiling, either on park or neutral, but the car cant be moving, if it is, then the ac stops blowing cold. the auxillary fans are working when the car is idiling but when the car is accelerated, the fan stops... help anyone??? also the vacuum pump is not working, i dont think its the pump itself, but when i play around with the fuse box, the actual fuse board that has the fuse for the vacuum pump, the pump will work for like 2 days then stops again, help anyone??? thanks!