My cruise control for 1986 Audi 5000 stopped working after I switched cluster. The speedometer is working. I tried putting the old cluster back in but that did not help. I went through the Bentley trouble shooting guide and that showed the switches and vacuum were all OK. The trouble is that there is no voltage coming from the blue and white wire in the cluster to the cruise computer. If I jump 12 volts to this wire, the vacuum pump activates and the car goes full throttle. Where is the sensor that sends the pulsating power to the blue and white wire? I have the cluster with the electrical NOT mechanical sender from the transmission.