I have a model 665.13183K800 dishwasher that seems to be working fine except for the fact that it's not heating at all during wash or dry. The heating element the the basin TCO are fine as I have tested them separately. I'm thinking maybe it's a relay. The control board is W10056352 REV B. I've been able to trace the circuit and deduce that the hot side of the heater is switched via relay K1 and the neutral side is switched via K3. Searching the internet for that control board and its replacements, I noticed in images that the K3 relay is sometimes black, sometimes red, sometimes white. To me that's a clue that this relay has been replaced with different brands/models as the control board evolved. Thus, I'm suspecting this K3 relay might have failed.
I'm searching for a couple of things.
1. A wiring diagram/schematic would be helpful. It's not so important, as I've traced what's involved.
2. Diagnostic service mode instructions. I want to be able to tell the control board to turn the heater on, or have it run through a short cycle and know when to expect the heater to be on.
If the relay isn't the culprit, then maybe it's the temperature sensor, which I think is part of the turbidity sensor. Parts diagrams are vague about that.