Most odd, it starts and drives as normal but pressing the function switch has no effect, the dash display stays the same so I can't check water / oil temp. The click action feels the same and the ribbon cable seems intact with no dodgy solder joints. Anyone else had this before?
Thanks Nick, I've unplugged and replugged both ends of the cable so as you say most likely the switch itself. Think I'll try and blast it with contact cleaner Never a dull moment with a TVR!