Unlike the 1968 Cougar headlight switch, the 1967 and 1971-73 version does not have the three vacuum ports connected to it. Don't be fooled . . . Most vendors will sell you a Mustang switch and tell you it is the same. Visually it may look the same but internally it has a circuit breaker designed for a two headlight system, the Cougar has four headlights. If you only use the low beams you would be fine but if you have all four lights on you will soon experience a blackout. If your original used switch also is cutting out it may be because someone installed after market bulbs that draw too much or your switch needs replacement.
NOTE: does not include C-shaped spacer / adapter bracket for mounting to the dash. Use your original, or ask about our used units.