You might ant to check fuses in the Power Distribution box in the engine compartment......I assume it is still near the air intake snorkel on Ford F53 chassis. For fuse assignments you can down load the owners maintenance pdf from Ford (free) for your F53 chassis....I assume 2016 chassis for a 2017 coach......try this link, but I am not sure it will work: Look under fuses if this link just gives you the whole manual:
http://www.fordservicecontent.com/Fo...US_12_2015.pdf
If PDB fuses or relays are not the problem then check for a good ground connection on the main wires that typically terminate under a grounding screw on the chassis radiator mount near the right side of the radiator. Could also be just a bad light switch on the dash too.