hello all second thread cant find my first from last year otherwise id update it, this a 84 original AC truck no longer hooked up but just has luke warm heat and air flow through defrosters for windshield ,i am now living at 9000 feet in Colorado and need it . i know its a flapper door i just don't want to tear the friggin dash out I've done it before on second gens and its a all day affaire , i have access to driver side and can see actuator for vent to defrost is working but cold to hot actuator i cant see and air flow and heat is somehow half blocked aim guessing any suggestions would be greatly appreciated .need to add i do not believe heater core is plugged ,in and out hose to heater core is hot and flow is good . checked intake to fan its good .what its not =bad thermostat ,plugged heater core ,fan