phishyninja

Your 78 won't have the 'heater' valve (monovalve).

You will probably need to install a manual ball valve or something like that and then bypass the servo by disconnecting the water lines and connecting them together. This new valve would be on in cold weather and off in warm. Not as nice as automatic systems when they work, but sure beats freezing.

Not sure what you will need to do about the fuse, does it prevent the heater fan from operating?

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150