I have a 1980 300TD with the ACC I system that I am currently troubleshooting. There is definitely a leak in at least one of the change-over valves located behind the pushbutton climate control unit.

Most sources reference 5 change-over valves, each with a two-pin, two vacuum connection set up. My car has only 3 change-over valves, and each one is a two-pin, three vacuum connection set up.

They are made by Pierburg but are cylindrical with brass housings. I have searched using the serial numbers on the valves but with no luck. The copy of the EPC I have access to shows them but has no part numbers. Does anyone know if they have Mercedes parts numbers, or have been superseded by a newer part?

There is a newer two pin, three connector change over valve (0015407097) that is listed as 'general use' for the W123 but I have no idea if it will work in this application.

I apologize for the long question but it's like these things don't exist.

Thanks

Michael

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