My wife said we have a problem with our dishwasher (Whirlpool WDT920SADE2). The dishes were not getting clean, and the soap dispenser opened, but soap was still dribbled down the inside of the door and on the silverware caddy.
I'm not the handiest guy; it took me several days to go through the trouble-shooting process, watching multiple videos and trying different things. My initial guess was that the soap dispenser was opening too late. (This turned out to be wrong.)
I started off by running a full (3-hour) and quick (1-hour) cycle, stopping it occasionally to check what was occurring inside. I realized that the water was room temperature and the heating element never activated.
I took the kick panel off and found the instructions for the installer, which explained how to activate a diagnostic cycle (Press any three keys in the order 123-123-123). I had to read the instructions about 10 times before it started to make sense to me - the test intervals are numbered backwards, from 26 down to 1; very counter-intuitive! Anyway, the test showed function F7 (heating), error E1 (no heat). The notes for F7-E1 said that either the heating element was bad or their was a circuit problem where the heating element was not being turned on. They also said that in case of a heating problem, the Control Unit would disable the heater but keep running the full cycle. We always run the hot water at the sink before we start the dishwasher. This explained why it took us a while to realize there was an issue with the dishwasher, because the cycle would complete normally. It also explained why the soap was still there at the end of the cycle - the water was too cold to dissolve it.
To solve this, I first watched some youtube videos on removing/testing the heating element. It took me a long time to remove the heating element, mainly because it was really hard to get my electric wires disconnected so I could pull the dishwasher out from the cabinet. My wiring was placed more awkwardly than the wiring in the demonstrations. Murphy strikes again! Anyway, after testing, the heating element was just fine.
Next, I looked at all the wiring from the control unit to the various sensors, because some people had broken wires. Mine all looked brand new.
I was a bit at a loss at this point, since everything checked out ok. I knew that somehow the signal was not being sent to the heating element to turn it on.
Grasping at straws, I watched an AppliancePartsPros video on the turbidity sensor and decided to take it out to look at it. It was really easy to remove; in hindsight, I didn't even need to disconnect the wiring to get to it on my dishwasher. It was very dirty and looked like it might be compromised internally, so I decided to order the part on Friday around noon. I was thinking, if this doesn't work, I'll have to either order a new control unit (based on the notes in the install guide for F7-E1) or call in an expert, depending on the cost of the control unit.
The new turbidity sensor arrived the very next day - amazing service! I had told my family I wouldn't be able to continue work on the dishwasher till Monday, but I got it installed in record time and ran the test cycle Saturday afternoon. Voila - I now had heat!
One weird thing; the F7-E1 kept showing up. I thought it would auto-clear, but when I ran another diagnostic cycle it was still there. I finally figured out that I had to press the HI-TEMP button during the test interval right after the 4 customer codes are shown. (I think it's interval 22). You have to be quick because the interval is only 6 seconds long.
Anyway, I got my dishwasher all to put back together and it's working great now, so the issue was definitely the turbidity sensor.
Kudos to AppliancePartsPros for their great step-by-step videos and their quick parts delivery!