1999 dodge caravan heater blows cold air?

First thing to check is open hood and feel heater hoses going into heater core located on r/s of vehilcle if sitting in driver seat.If they are both very hot and feel the same temp,blend door in heater box is not operating correctly.If one heater hose is hot and the other is cooler than chances are the heater core is plugged.In either case a professional would be your best bet for repair.Hope info was helpful.