If your speedometer completely fails look at the angle drive first before suspecting the cable. easily checked by disconnecting the speedometer cable then lifting the car and putting it in gear to see if the angle drive spins, the part is easily replaced. always try to buy a new one as this is a wear part. purchase a speedo angle drive seal at the same time to stop the transmission fluid leak. it fits on the drive gear in the rear tail cover and is easily removed with the rear 13mm headed set screw. (you will have a fluid spill when this is removed so get ready!) refill with 80/90 weight oil only.