Sounds like your coach was similar to our 2013 ACE which had the two low point drain valve "pull rings" on either side of the water pump in an outside cubby. Much easier for me to find than you from the sounds of it. Attaching a simple plumbing schematic ( we don't have any fancy "cant leak" valve system) in case new RVrs with simple systems need to understand a simple system with basic 3 valve water heater bypass.
__________________
|