KitchenAid dishwasher KDTM504EPA0 - no water dispensing - float switch and inlet valve OK

[Tripp Knightly]

This dishwasher is not getting a drop of water sent through the fill tube.  Inlet valve is checking fine (1.2 K ohms resistance on both an old and new one, plus neither work!).  Float switch works.  The fill cycle sends ONLY 16V on the wire to it when it should be 120.

Is this pretty much guaranteed to be a bad control board?  I would think the door switch can’t be involved because the dishwasher does “run”, even with no water getting into it.

This DW has had prior issues with the “self cleaning” filter in the circulation pump getting obliterated, but this water fill issue is either unrelated or (perhaps?) from board damage that is consequential from the pump getting jammed by the broken filter.

[16345Ed]

10 hours ago, Tripp Knightly said:

The fill cycle sends ONLY 16V on the wire to it when it should be 120.

If this is fact. I’d double check from the board to eliminate any wiring issue. If same result it sure seems like the board. 

[Tripp Knightly]

Thank you.  I had a similar later thought wondering if my probes were tenuously attached.  Anyway, I’ve since pulled the cabinet panel to get the board.  Which was fun in and of itself as my remodelers decided to use heavy-duty mounting tape instead of the prescribed screw hangers.

I eventually got to the board and tested the inlet valve wires for continuity (confirmed) and then board voltage at the inlet valve pin-outs.  The unit was on its back but I ensured the float switch was activated.  I got no voltage at all and waited a few minutes into a couple different cycle types.  On the board I got 120V at the drain pump pin-outs on activating a cancel/drain cycle so nothing amiss with my testing it seems.  Nothing visibly bad on the board like bulging caps, scorches etc.

Guess I’ll really need the new board I’ve ordered.

[Jake's Repair]

Any updates on this? Did the board fix it?

[swiftappl]

You may have an "F9" Fuse blown in the board. I am thinking if the triac does not close....about 16 volts will be present.

Also, a circuit with a triac in these boards MUST have the load connected in the circuit to activate the triac.

Fuse Service Check:
F9 = Small-triac Load Fuse.
Check operation of loads during the Service Diagnostics cycle.
■ If any of the triac loads work, F9 Fuse is OK.
■ If all triac loads fail to work, F9 Fuse could be open. See “Fuse Resistance
Check.”

Fuse Resistance Check:
1. Unplug the dishwasher or disconnect power.
2. Measure resistance of F9 Fuse.
NOTE: Fuses are on the bottom of the Control Board but can be checked
from the top side. See “Control Pinout” diagram.
■ If resistance is < 3 Ω, then fuse is OK.
■ If resistance is > 3 Ω, then fuse is open.

What To Do If Fuse Open:
Inspect and check resistance of all loads on fuse. If any loads are open,
shorted, or have evidence of overheating or pinched wires, replace them.

If you fail to check the load circuits and they are shorted or lower than normal resistance...

You will blow the fuse in the new board!