Open your glove box, and shut the switch off. It is located in the upper left position. It defaults back to "on" every time you shut off the car, and turn the car back on. Other than that, it will have to be programmed "off " in the PCM if you want it to be permanently off. Or you can move the switch to a more accessible location.
2014 Chevrolet Silverado LTZ Z71 5.3 Aluminum V8 (My daily)
2007 Pontiac G6 VL 2.4 I4 (Wife's Daily)