If it's like mine, and I think it is, it's thermostatically controlled and will come on when the temperature at the heat exchanger reaches a certain level (100 degrees F, I think). It will not turn on immediately when you flip the switch. It is a 12 Volt fan.
I'm sure it is fuse or circuit breaker protected, so you might check that aspect.
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew