1993 Ford Bronco A/C Heater Vacuum Diagram - HVAC Door Vacuum Routing (EVTM 54-1)

This document is a screenshot from Ford's Technical Service Publications EVTM (Electrical & Vacuum Troubleshooting Manual) software, page 54-1, titled 'Air Conditioner/Heater, Vacuum.' It shows the complete vacuum routing schematic for the A/C-heater system. Vacuum is supplied from the vacuum distribution system (referenced on pages 142-1 and 142-2) through a black line to a vacuum check valve and vacuum tank, then through the HVCB (Harness Vacuum Connection Block) and FCCB (Function Control Connection Block) to the A/C-heater function selector vacuum valve. The selector valve diagram shows port states for each mode position: MAX, NORM, VENT, FLOOR, FLR/DEF, DEFROST, and OFF. Color-coded vacuum lines run from the valve: red to the floor-defrost door vacuum motor, blue to the panel door vacuum motor, yellow, and white lines to the outside/recirculate door vacuum motor. The lower half of the diagram is a cutaway of the HVAC plenum showing the heater core, evaporator core, blower motor and wheel, temperature blend door (cable controlled), floor-defrost door, panel door, and outside/recirc air door, along with airflow paths to defrosters, demisters, floor outlets, and instrument panel registers. A legend defines V = vacuum, NV = no vacuum, PV = partial vacuum. A reader can trace vacuum supply, hose colors, and door actuator functions for diagnosing HVAC mode door problems.