Heater only works when moving. It blows out cold air when the truck is at a stoplight or something. Any idea's?

Brad


95 Trooper,3in Lift,15x10 AR-23 Wheels, 33x12.50 BFG AT's, SuperWinch Hubs,Rock Sliders,Tie-Rod Shields,Cross-Drilled Brake Rotors,ARB Bull Bar...,looking for cheap winch.