Speedometer and cluster

My problem is this; First thing in the morning and usually the next two starts the car functions normally. On the third or fourth attempt to start the car. The three clusters on the dash will remain on (yellow) and the speedometer will not work. It seems to happen when the temperature is around 1/4 to 1/2 hot on the gauge. Sometimes it has happened during driving when the engine is hot. All of a sudden the speedometer stops and the cluster lights are on. On a longer drive the speedometer will work and the clusters are off for the entire trip but not on the way back. We have replace one wheel sensor and that has not solved the problem. We have disconnected several temperature sensors in our process of elimination but have not found the solution. Do you have any suggestions where the problem may lie?