1979 Ford Bronco/F100-F350 Heater & A/C Electrical System Wiring Diagram

This is page 41 of a Ford electrical reference guide (uploaded as part of a 1979 Bronco / F100-through-F350 set), covering the Heater and Air Conditioner Electrical System. It explains that the A/C-heater system has six basic electrical components: blower motor, compressor clutch coil, de-icing switch, blower speed switch, blower motor resistor, and the system OFF-ON/clutch switch. A detailed trouble-shooting flow addresses a blower motor that does not run in any position (check fuse 3, a 35-amp fuse hot when the ignition is in RUN), a blower working in only some speeds (checking wires 270 bk/y, 268 r/bk, and 269 bl/r at resistor connector C604), and a compressor clutch that does not engage. A full-page schematic shows the circuit from Fuse 3 through the A/C function control switch (Off, Vent, A/C, Hi/Lo, Heat, De-fog, Defrost), blower switch, resistor pack, de-icing switch, A/C clutch solenoid, and blower motor, with wire colors and connectors C604, C605, C613, C616, splices S603/S701, and ground G601. Tables list blower switch continuity connections by speed and component locations, plus a note that two types of blower switches with different terminal codes were used.