Unplugged unit.
Removed all the water out of the internal pan.
Took of outer panel on right side of unit facing unit
Removed sensor and O-ring.- they are attached to the bottom of the central drain pan. sensor is hand tightened 1/8 turn. very simple to remove.
Replaced with new part.
Reassembled - it runs great.
Hardest part is my hands were large for small space.