REpair error code F20 on Fisher & Paykel French door refrigerator?

Hi,

My Fisher & Paykel fridge has a F20 error code displayed. I have replaced the 7 wires under the right hand door hinge cover from the connector to as close as possible to where they disappear into the fridge door. I checked the wiring with a resistance meter and none of them showed a very high resistance so I figured the connections were good.

I have checked the resistance of the heater in the door flap - 14 Ohms as measured on the terminals in the plug located below the left hand hinge. I also measured 12v on the other side of the connector. On this basis I think the heater is OK.

Any idea what could be causing the F20 error?