It's over when the fat lady sings
Brother of The Benz, The Bob
Should the aux water pump fail on my 1987 300E, the MB Service Technican said I could by-pass it and experience no change in the heater performance.
Ofcourse I live on the Gulf Coast and it doesn't get very cold.
Not so on the mono-valve, you should check into it.
I don't understand your discription of where the damage was caused.
I gather it is on the inside of your Benz, in the A/C housing. If so, how could these two items being under the hood effect the housing? And what effect could the aux-pump draughing too much current and not opening a fuse burn a hole?
Do some diagnosing before you wholesale replace parts.
It must be silly ole me.
Happy Trails Beep Beep from The Spiderman in Houston!!!