Most likely a thermost open circuit or maybe the defrost timer on the rear (if fitted) is stuck in 'defrost' position - its in a plastic box on the back and can be manually turned with a screw driver. But i guess that all thats needed is a new thermostat - cheap. Isolate the supply, and remove the plastic light box - after removing the screw behind the lamp 'glass'. The thermostat phial tube just pushes down a plastic pipe inside - and the connections simply plug into a socket inside the box. Be careful as all this is a tad fragile - but a simple job if your careful.
The thermostat probably has 3 connections, 4,5 and 6 ... you should get a continuity test between all 3 when the thermostat is turned 'on'
If your unit is electronic controlled however... could be pcb - sensors - not an easy or amature job to identify really.
In the worst case the compessor motor could be open circuit but thats unlikely - if it is, its a professional job to fix - Buy a new one! lol will be cheaper. (connections on the motor itself are a nightmare - but if you carefully remove the starter unit you will find three push on connection pins on the motor - you should get a circuit reading between any 2 of the 3 pins. if any are open circuit the motor is duff) - probably not an amature job again.
Well you did ask! cheers
Robert, October 2009
