The speedo in my R129 500SL is broken. The speedo needle has a mind of it's own from pull-away and never registers a road speed. A Merc specialist and a very competent auto electrician have checked everything and confirmed the NSF ABS sensor as good therefore, it's the clock at fault. The Specialist, along with others I've spoken to, also think that possibly when a working speedo is put into my car, I will regain power roof operation, which is currently not working, as the speedo has to send a signal to the roof control module to confirm that car is stationary? The same Merc Specialist checked every other aspect of my roof and said that there is no other reason why it won't work (apart from control module), as hydraulics, electrics and switches are all fine.
So, following all these findings, I have purchased a second-hand binnacle with a known good speedo and will take this out and put it into my binnacle (replacement cluster doesn't have SRS lamp, etc). Hopefully, this will provide me with a working speedo! The question is, does anybody know of a straight-forward way for me to adjust the mileage on the replacement speedo, to match that on the faulty speedo?
So, following all these findings, I have purchased a second-hand binnacle with a known good speedo and will take this out and put it into my binnacle (replacement cluster doesn't have SRS lamp, etc). Hopefully, this will provide me with a working speedo! The question is, does anybody know of a straight-forward way for me to adjust the mileage on the replacement speedo, to match that on the faulty speedo?