1986 Ford Bronco mist from heater

Your diagnosis seems right. Here's the proccedure: HEATER CASE - BRONCO & "F" SERIES Removal Disconnect temperature cable from temperature blend door and mounting bracket on top of heater case. Disconnect wires from blower motor resistor and blower motor. Disconnect heater hoses from heater core and plug hoses w/suitable 5/8 inch plugs. Working under instrument panel, remove 3 nuts retaining left end of heater case and right end of plenum to dash panel. Remove 2 screws attaching right end of heater case to dash panel, and remove heater case from vehicle. Installation Position heater case to dash panel and install 2 attaching screws. Working in passenger compartment, install 3 nuts to retain heater case and plenum right end to dash panel. Connect heater hose to heater core. Tighten clamps to 13-18 in-lbs (1.46-2.03 N.M). Connect wires to blower motor resistor assembly. Connect wire harness connector to blower motor. Position temperature cable pigtail on temperature door crank arm w/pigtail up. Be sure flat washer is placed under pigtail. Then, install a new pushnut to retain pigtail on crank arm. Position temperature cable flag to mounting bracket and install attaching screw. Check system for proper operation. Page 1 of 1 1/31/2010 .