my engine temp gets to normal temp and the air blows just little hot when cranked all the way up, i was told a couple different options involving the heater core and possible a heater control valve (if it has one). does a 2002 GP have a heater control valve? I can hear the the valve changing in the heater core when i switch from hot to cold, but not sure if it turns all the way. Any ideas on what it could be?