Plugged in the spare ECU today and the gauges moved, so not a wiring problem.
Put my main ECU back in, gauges dead again. Parked the car in a warm place for 1 hour and the gauges started to work.
VIDEO
VIDEO - HRW works fine when the gauges work.
When I took the car outside again, the gauges started to work intermittent and after 10-15 minutes they went dead.
VIDEO - Intermittent work.
VIDEO - HRW no longer works.