Siemens GS32NA91GB/03 Freezer

High folks I have a Siemens GS32NA91GB/03 Tall freezer that is not self defrosting. In the back top right corner just below the evaporator assembly there is a bank of plugs no I am guessing because the evap is frozen solid with frost that starting at the left hand side white plug with black wires is the thermal fuse or defrost stat, the next one along black plug white rubbery wires is the main defrost element the third one along blue plug green wires is the drain heater and last but not least fourth one along is the evap fan. the first two are open circuit, so before I start ordering parts can someone either confirm my suspicions or secondly send me the wiring diagram. Many thanks Neil