There are a lot of suggestions on the internet about replacing the circuit board. I thought I'd take a look at the board and maybe clean up any edge contacts. On inspection I found the adjusting knob for the fridge thermostat had snapped inside so although the knob would turn on the front panel it didn't actually change the setting on the pot which was set to the highest setting. I thought I'd add this in case anyone else has the same problem. Now all I need to do is replace the knob...
Jim
May 2009