If drawer doesn't open, is going to be failure of one of 3 things. Drawer is binding physically, the motor is failing, or the control circuitry is failing. I doubt that you will be able to find parts for a 10+ year old discontinued unit. Might just be best to replace it.
1999 Newmar MACA 3796 F53 6.8L
2016 Ford Edge Sport
Roadmaster Sterling A/T with Brake Buddy Select