GE Dishwasher GDT695SGJ0WW: Service LED is on solid green. No user control lights come on.

[LocicAl]

No lights on user control panel.

AC power is verified correct.

Pressing and holding the Select Cycle and Start buttons does NOT respond with display coming on.

Door latch switch measured zero OHMS so has continuity when door is closed, and does not when door is open.

Flood switch has continuity when actuated.

Service LED is on solid green on Main Electronic Control board (Part Number WD21X24901).

Recently had no lights on user control panel but pushing the reset button on the thermal sensor brought it back to life.  However, now this does not work.  This thermal sensor is part of the AC Harness Assembly Part Number WD21X24096.  Two of the wires go from the Electronic Control Board WD21X24901 to the heating element WD05X24776.  It measured zero OHMS on both leads so it has continuity, tested both plugged in and unplugged.  Resistance across one wire to the other was 16.4 OHMS plugged in.  The heating element also measured 16.4 OHMS by itself (unplugged).

I’ve read that at least some machines have a thermal fuse located on or near the User Control and Display Board.  I don’t see any reference to one on the parts diagrams for my GDT695SGJ0WW.  I disassembled to investigate but could not find a thermal fuse.
In research so far I have not read how one can diagnose for certain if either the main control board or the User Control and Display Board is defective.  These boards are expensive so I only want to order if sure I need one.  I appreciate any help on this problem.
 

[LocicAl]

I wrote in my post that pushing the reset button on the thermal sensor recently brought it back to life.  However, now this does not work.  I found a “thermistor output table” in the service information and got thinking that since it measured ZERO OHMS on both leads perhaps it went bad.  Research revealed that with a completely open circuit the thermistor is likely to be faulty.  I’m ordering the AC Harness Assembly Part Number WD21X24096, and I’ll post the results.

[Vance R]

Steady on led indicates - UI personality not set communications - lost between UI and MC. 

[LocicAl]

The AC Harness Assembly Part Number WD21X24096 arrived today.  Resistance across the thermistor leads measured zero ohms, which is the same as the existing one in my dishwasher.  

I now noticed the reply by Vance R.  Looks like I need to order the user interface board.

[LocicAl]

SOLVED: Replacing the User Control and Display Board WD21X23462 fixed it. Earlier I ordered the AC Harness Assembly Part Number WD21X24096 because I thought thermistor should have more than zero ohms.  However, the new one also measured zero ohms.  I installed it anyway but the symptoms did not change.