My heater on 96 Villager blows hot air for a while , but after drivind for a while you can hear it blowing but no air comes out. Tha accumulator/drier frosts up something terrible. The rear heater works fine. Please help with this problem.

Sounds like you may be runnig your ac and not your heat. You may also have a bad HVAC unit. Thats the heat and ac control unit for short. Do a search there are ways to test them I have wrote up few.