I can save you time. The schematic is something I cobbed together for GoMoG many, many years ago That systems is not very smart. It places a heating system one cannot shut off next to a flow of cooled air. The result, as you can well imagine, is at best a damp humid flow which is non-ideal and rusts the internal control. I was encouraged to look at it, though I am not a fan (PUN!) of Morgan aircon. The unit was designed by a small aftermarket firm in the UK. Unlike most Morgan suppliers, they were unhelpful, but it is not hard to see where they went illogically wrong.
1. one can merely use a mechanical or solenoid controlled shut off valve that shunts the unwanted hyper-hot coolant away from the cabin matrix when using the air conditioning. In fact, I adopted a solenoid device to use to stop the hot flow to my non-AC system rather than the tortuous clutch cable pre-AC cars are fit with. Works a treat at the press of a button.There are many other automobile companies that use the gomog system. BMW is merely on of them.
2. one can rip the entire system out and replace it with something smarter. Many have done so. There will be no loss as your internal controls are probably rusted out anyway and the system is designed to fail.
https://www.gomog.com/allmorgan/CabinHeaters.html#BETTERLorne.
