I have a side by side model number ED20TK and

The overfilling is most likely caused by defective water control valve on the ice maker side. The replacement for your model is a=> W10408179 Water Inlet Valve

The water fill adjustment can be found in the Ice Maker Troubleshooting Service Manual These settings can cause too little or too much by turning the set screw so use caution. I will be here should you have questions or comments, Thanks Sea Breeze

What is the model number of the unit?

Replace the water valve ( pt # WR57X10051 ) . This piece is what the wall water line connects to on the refrig . Also , due to the age of the refrig , I would suggest removing the ice maker ( 2 screws ) and inspecting the inside of the mold for coating disintegration which would cause water to seep thru the uncoated aluminum ( or bubbled coating ) causing the ice maker to leak , but , appear to be overfilling . In this case , replace the ice maker instead .

If it overfills and drips, look for an adjustment behind the plastic endcover with a +/- on it. - is less water.

If it continuously drips, replace the water inlet valve on the back where the house water supply comes in.

check water level float/inlet valve

I have had a similar problem several times. What I have found is that the ice tray coating has begun to flake off. Then, the ice sticks or partially dumps. Next more ice builds up and when the valve opens the water runs over the partially emptied tray and spills into the bin making "icebergs". The remedy is to replace the tray or if that is not possible, then, the whole icemaker. In fact, I have one down stairs to put in tomorrow. They don't seem to last more than about 4 years or so.

Hello , that is exactly what is happening this is caused by 1 of 2 things.
1- the module/control on the front of your ice maker is sticking during its cycle and over timing the fill stage.
2-your inlet valve located in lower rear at water line connection is not sealing causing water to seep through line to ice tray and overfill.
Both are common issues and the most cost efficient way to repair this is to order the ice maker kit that contains both the ice maker and the valve so you can guarantee the fix.
You can purchase on line with your model number for around $100 Calling a service company will cost at least $150 changing only one of these parts or about $200+ for both.
If you have any questions please ask and let me know how it goes.

Phil

The problem is in the water valve.
The water supply line going to the Ref is connected to a water valve. This valve is not shutting off completely which causes water to drip into the ice maker. This dripping will freeze and eventually completely block the fill tube in the freezer.

not familuar with the brand but sounds like one of 2 issues
if it is overfilling making ice cubes larger than normal, adjust the ice maker fill time if it is possible
icemaker fills and cuts off but water valve seeps water after the fill causing the water overfill
one of the 2

Pressure difference between the two water supply systems is the cause of the overfill condition. You may have to install a water pressure regulator in line to the ice maker water supply. Or you can try to control the flow by throttling the supply valve to the refrigerator.