If the light has a constant 12 volts on one side of it, and the sensor adds or removed a ground to the other side of the lamp to turn it on or off, the sensor is the most likely culprit. However, if the sensor is unplugged, that should give you a light that is constantly on or constantly off. If it randomly goes on and off, I'd really check out the wiring coming from the sensor. It's likely chaffed and shorting out intermittently.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.