I don't know if I have a Greystone or not, but I assume Voltage uses the same vendor for all their units. I took mine out to fix a leak. It's just held in by 4 screws and then you gently lift up. Comes right out. They are powered by a normal 110 outlet plug, perhaps the unit isn't plugged in, or maybe a fuse issue. At the very least I would imagine there is a label with model information on the back. Good luck.
2015 Black F-350 Platinum Diesel Dually Crew Cab
2019 Riverstone Legacy 38MB (Full Paint/All Options)
2015 Voltage 3990 (Full Paint, All Options) Sold 6/18
2005 Harley Ultra Classic w/too many miles