hi u need to check if it is electrical drive or cable, if u look on the right hand side of engine bay on the gear box at the back quite low down u will see either a black cable coming straight up and in to the bulk head ( metal wall between engine and inside the car the cable is connected with a large bolt and the cable goes threw the center of the nut un do it and connect a drill to it and spin it see if the needle goes up if it dont its the cable if it does it is the drive gear in the box to change the drive gear there is a roll pin giong threw the side of the casing hit it out with a bunch and hammer and pull the drive out may be siezed in so might be tight the plastic gear is probibly worn out this is common with old fords. if there is wires goint to it as they changed the set up after a sertin year there should be 3 wires 1 negative 1 positive and the other is positive signal to clocks check for + feed and good earth going to it and if u juck up one of the front wheels u can put car in to gear and start it up so wheel turns check the signal wire for current flow when car is driving in gear if ther is nothing the drive has gone same drive as the cable set up pull it out and check for worn gear if u get a positive current flow from the signal wire then u have an open circuit from the drive to the clocks and that is whole different ball game do the voltage test on the switch when it is conected as it needs the power feed to work hope this helps
tim lewis, September 2007