Speedometer Help

Inspect the cable both under the car and behind the cluster. If OK, remember that there is an inner and an outer part. Your problem is probably the inner cable or the head. Disconnect from the back of the cluster and remove the inner cable. Is it obviously broken? Put drive end of cable in a vise and check cable "wrap". Is it bad? A local speedo shop can make you a correct new one. After dealing with inner cable, then we suspect the head.