Why is my defrost cycle too long

SOURCE: Ice maker

Smitty, if this is a GSS20, General Electric model you have an electronic model ice-maker. There is no water adjustment screw. Here's how the fill works; when the harvest is finished the icemaker will enter the fill cycle. The amount of water entering the mold is controlled by temperature. Before any water enters the mold has to be at least 35.6 degrees. Water entering the mold will cause the mold temperature to change, effecting the resistance of a thermistor. The first fill activates the water valve for 5 seconds. The thermistor checks the temp of the mold. If the temperature of the mold exceeds 39 degrees the icemaker will end the fill cycle and enter the freeze cycle. If the temp of the mold is still below 39 degrees, the control will assume that an insufficient amount of water entered the mold, and energize the water valve for another 2.5 seconds. Now it will check the temp again. If the mold is still below 39 degrees a third fill of 2.5 seconds will occur. You could have a thermistor that's out of spec. Usually on this model, the power LED on the icemaker will flash 1/2 second on and 1/2 second off if the thermistor is open or shorted. You could have a water valve that is not seating properly and allowing more water to enter the ice-maker. You can run a cycle on this ice maker by turning it off, then on again and pushing the feeler arm in 3 times within 15 seconds. Watch how the fill works. Anyway, outside of the excellent information posted by 24 seven, This will give you an idea of how the icemaker works. Catriver.

SOURCE: Ice cubes melting then refreezing in clumps

check the flap door to see if it is slightly open letting warm air in

SOURCE: Ice cubes made by ice maker become large fused chunks over time.

Ice cubes will deteriorate over time if not used. They shrink due to defrosting of the freezer and will become stale.
Once the ice bin is full, turn the ice maker off until you use the cubes and or dump the cubes every 3 or 4 days and start over.

SOURCE: DSS25KSRD SS GE Adora refrigerator- ice in tray

It sounds like the # 4 thermistor is bad . You will have to remove the lower inside rear freezer panel ( 2 or 4 screws ) and on the top of the coils , you will see a 1 " long torpedo looking piece , clipped on , with 2 white wires going to it . Part number WR55X10025 . This thermistor , tells the maon control board , the temperature of the freezer coils ( evaporator ) and when to defrost and when to stop defrosting and turn the compressor back on . There is also a defrost thermostat which cuts the heater off to keep from over heating , but I do not believe this is part of your problem . You should also replace the # 5 thermistor , located behind the oval grill , mounted on the lower right side of the freezer . This thermistor , tells the main control board , the temperature of the freezer section .

SOURCE: Symptoms: Ice cubes melt, drip then refreeze causing

are you having any cooling problems? take a look at your ice cream, if you have any. does it look like it has melted and refrozen? if so, you have a cooling problem, and that is causing ice to melt, then refreeze. if you have no cooling problems, then you may have a faulty water valve solenoid, or even a faulty icemaker.