slemnah wrote:
That looks like a heater core shut off valve to stop hot water from going into the heater core. It looks like it is closed. Try your dash heater and see if any heat comes out of it.
Steve
A common problem with many motor Homes is the flow control valve to the heater core.. Putting in a manual cut off is the lowest cost repair. and by the way, likely the best repair.
Follow the hose, If it connects to the the engine block or water pump and to the firewall, or to a box with a 2nd hose next to it then this goes to a 100% certainty instead of a very very strong suspicion.