I had the instrument cluster out of the car and a few days after the speedo stopped working. Removed the cluster again and ensured that all connections were good but still no joy. Scanned the car for errors and only got the oil level sensor fault that I've had for a few months now, but nothing for the speedo. Swapped over a speedo sensor that was sitting in an S3 box out the back of a friends house for the last few years, still nothing. Plugged in the VCDS again and ran an output test for the instruments and all working, the speedo and rev counter go through the motions as they should be.
Correct me if I'm wrong but if the output test is fine everything from the ECU to the instrument cluster is good. And if there is a fault at the speedo sensor (including wiring) it would show up on a scan. What am I missing here?