< I cleared the frost every time I went to the customer's home .>
How did you defrost it, with a heat gun or using forced defrost mode?
Did you test the defrost heater and prove it works, correct current/resistance?
Did you defrost both evaporators?
Are the drains for both evaps clear?
Do the doors close and seal completely by themselves, meaning they can't be left partially open?
Are there containers of liquid/water/soup uncovered in the fridge?
Is the icemaker dripping any water into the fridge?
Is there any water under the cool select drawer or crisper?
Are there any error codes?
I seem to recall a tech bulletin regarding some models about moving the thermistor on the evap to achieve a better defrost.