That switch controls a relay which is most likely where your problem is. You should visit the tiffinrvnetwork.com for help with your specific model of coach.
BTW, most everything Tiffin can be purchased from Tiffin. Give the store a call.
Roger & Mary
2017 Winnebago Navion 24V (Sold)
2014 Tiffin Phaeton 36GH (Sold)