A: Remove the heater/air conditioner assembly and place it on a work bench. Locate and remove one retaining nut from the blend-air door pivot shaft. To remove the top cover from the air conditioner/heater housing, remove the crank arm. Disconnect the vacuum lines from the defroster and panel model vacuum actuators and position them out of the way. Remove the three heater/air conditioner cover screws that point up at the defroster outlet chamber, the two screws that point up at the air inlet plenum, and the eleven screws that point down into the housing. Lift the cover from the heater/air conditioner assembly. You can now remove the heater core (or the air conditioner Evaporator unit). Installation is the reverse of removal.