Ice develops at back of fridge
dave here hope i can help
I would test the defrost timer, defrost heater or defrost limit switch
TESTING AND REPLACING THE DEFROST TIMER
This timer activates the heater that melts frost in the evaporator for 10 to 20 minutes every 10 to 12 hours. In the process, it turns the compressor off and on. If it fails, the compressor may not run. Or the heater may not go on, eventually causing a hidden ice buildup that blocks the cold-air flow and disables the evaporator fan. An access hole lets you test the timer. If the timer isn't in the control panel, look behind the front grille or behind the rear access panel. If the compressor fails to run turn the timer until it clicks. If compressor goes on, timer is faulty. If unit isn't defrosting automatically and turning timer stops compressor or fan, timer is faulty.
Before replacing timer, spray it with electrical contact cleaner through access hole and turn it a few times. Stop just before a click and wait to see if timer advances on its own.
To replace timer, unplug the refrigerator and open control panel. Remove screws holding timer to panel and pull of leads. If wires aren't in a plug, move then one at a time to new timer.
EVAPORATOR AND DEFROST HEATER
In a frost-free unit, the evaporator coils, their fan, and the deforst heater are located behind the freezer's back wall or under its floor. The fan, which circulates cold air between the coils and the two food compartments, is controlled by the door switch, the thermostat, or both. To check the fan, open both doors, wait for the compressor to go on, and hold in the door switch. If you can't hear the fan running, test the fan(below).
The defrost heater, which melts frost on the coils, is cycled on by the defrost timer(above). If the frost melts before the end of the defrost cycle, the defrost limit switch turns the heater off. The heater may be a metal rod, a wire wrapped in foil, or a coil inside a glass tube. All are tested the same way. Test terminals for the heater are often located in the control panel or under a doorjamb; check the wiring diagram. Or test the heater leads inside the evaporator compartment.
TESTING THE EVAPORATOR FAN
To remove the evaporator fan, unplug unit; open back panel(or floor) of freezer. Then unscrew housing holding fan, and take off leads going to fan motor. With VOM(Volt-Ohm Meter) on RX1, probe motor terminals(except green ground wire terminal). Look for moderate resistance(50 to 200 ohms). Replace fan if much lower or infinity.
TESTING THE DEFROST HEATER
Open control panel. With VOM on RX1, probe test terminals. Look for 15-to 100-ohm reading. If infinity, turn defrost timer(as above); retest.
TESTING DEFROST LIMIT SWITCH
Trace and disconnect leads. With VOM on RX1, probe leads. Look for infinity reading when switch is warm, zero after 20 minutes in working freezer.
Hope this sources your problem
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Jul 20, 2008 |
AEG Santo U 86000i Compact Refrigerator