my heater is terrible. Te defrost works ok gets warm but the rest of the setting seem to blow luke warm if not cool air. No sign of ay coolant leak inside the cab or out to indicate heater core. Like I said the defrost gets hot! n ideas what it could be. This is after up to operating temp so I dont thik its a thermostat. Is the heater core a incrementale thing on this truck where as it only works so-so before going bad? How hard to replace the heater core? could it be a simple repair? Thanks so much.. signed cold in ohio

 

it wont be the heater core all that is is basicallly a radiador that radiates heat into your airbox. it could be your switch is pooched or even your air box which is a real pain in the ***. i don't mean the under the hood air box i mean the one inside your dash