UK Car Repair: mileage counter corsa, gearbox, speedo

Question
hi there..i've got 98 corsa with electric speedo and everything's working on my dash just counter mileage (both) don't work..can you help me please?
thanks for your answer

Answer
The drive unit is a transducer on the transmission, it is either faulty or perhaps disconnected, i'm not sure exactly where it is located but call the dealer to get a price and ask them "is that the one on the gearbox?" they will likely tell you where it is.