Heater Diverter Valve - 2007 LC 100?

[LastTry]

Today read about this on a FB Toyota Lexus page. Is there a heater diverter valve and if yes, a point of failure? Besides the infamous T's, its a mystery unable to sort online.

 

[badlander]

No water control valves that I know of on 100's. Full time flow through both heater cores. Only an air control valve in the hvac system.