Right I get it.

Mechanical speedo in dash - electronic speedo connection on 722.303

As you have the 722.416 that could be the solution - but why it wasn't used in the first place is a mystery to me. Could it be bust?

You say it has been outside for 7 years? I guess it will be dead.

I'm not sure how advanced the electronics for the electronic speedo are - it might be as simple as the tachometer - ABS isn't necessarily a problem but the biggest one is finding a W123 1985 electronic speedo => all in all I fancy your chances of finding a good 722.416 or a 722.315 more than I do one of those...

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!