Topic: Factory AC Fan Wiring Harness Extension

[Angela]

Application: 1970 Mach1 with factory AC

Could anyone please help me clarify which wire harness I need which connects to the heater-box/Fan housing? I believe it's a short (perhaps 6") harness and mine was missing when I purchased the car. Some sources suggest the harness for use with factory AC has five (5) wires and PN=C9ZA-19945-B. However, other sources show the same exact connector with only four (4) wires. I do not know which is correct
TY!

[midlife]

4 wire version is non-AC.  Depending upon where the AC mode switch was placed, either harness could be used.
1970 is a year of transition of wiring for non-AC and AC cars.  The heater boxes are different, and the position of the resistor wire assembly (where the 3 prong plug goes) is far to the left for AC cars.  These changes occurred in the 69 model year, but wiring length changes didn't get sorted out until well into the 70 model year.  These extensions were an attempt to remedy poor fitment of the harness to the heater switch itself.  Similar extensions were applied to the portion that mated with the heater box.