Customer called to say that the evaporator coil is clear but all around behind the evap unit is a big block of ice. I asked and the outer portions of it are thick frost although the inside of the ice mass is apparently now solid. I asked how long it has been that way and they told me they keep a crowbar in there now and for as long as they can recall - to use to smash the ice down with. <g>
I haven't seen it yet but this sounds to me like a bad fan delay. That is: it has failed closed and the evap fans come on immediately following a defrost.
Anything else it could be?