My erstwhile '84 190E 2.3 (USA model with AC, so it also had an auxiliary electric fan in front the condenser) had an electromagnetic fan clutch for the engine driven fan rather than a viscous fan clutch like on my current '88 190E 2.6. So on the 2.3 it was either completely off or locked full on. I don't recall if it had a relay, but probably so.

I can't answer your question, but it seems to me if you have the original fan and clutch assembly you should be able to reinstall it, but the difficulty might be what if any wiring modifications were made.

You need to look at the wiring diagram for your car and understand what if any wiring and or relay changes you need to make to bring it back to the OE configuration.

Duke