I'd start buy pulling the cluster from the dash and back probe terminal A5 and reconnect the harness to the cluster. Next connect the positive lead of a multimeter to the back probe and the negative lead to a good ground. Just set the cluster back in its place and start your hoe, select drive and just let your foot off the brake and watch the voltage on the multimeter. It should gradually change with your acceleration.
If not then use a multimeter set to ohms to check the resistance in the wire between the cluster and the PCM. Unplug both and using the same terminal on the cluster harness (terminal A5) and the PCM harness terminal 50. The meter should read approx. .3 ohms (very minimal resistance) If it reads OL than unfortunately you either need to run a new wire from PCM to Cluster or follow the harness and try to find where the wire is fouled/broke.
Unfortunately, I'm having trouble uploading the wiring diagrams I wanted to show you.
