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Whirlpool WDT750SAHZ0 fills, but doesn’t wash

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
Model Number
WDT750SAHZ0
Brand
Whirlpool
Age
1-5 years
Hello everyone,

My current dishwasher will fill water but won’t wash. A/o today the circulation pump has been replaced and still the wash cycle doesn’t occur. I ran diagnostics and now the board is saying the float switch is faulty. I decided to see if that was accurate and by my surprise the float switch had continuity.

I’m beginning to think the board is bad? The sound I hear when the pump turns is just a humming noise, is that normal? Do you think I have a short somewhere?
 

Storyteller12

Premium Member
Joined
Sep 3, 2022
Messages
20
Location
VA
Have you tested the circulation pump for 120v to make sure it’s getting power?

Also have you made sure the float switch wires have continuity to the control board? Sometimes the wires make bad contact or can break.
 

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
Hi, I haven’t tested the circulation pump as a brand new one was just put in yesterday. I’m hearing a humming/clicking noise when trying to start the wash. I haven’t checked the wires yet, do you think the wiring harness could be bad?
 

Storyteller12

Premium Member
Joined
Sep 3, 2022
Messages
20
Location
VA
I have had a bad connection in the wire harness on another similar model by whirlpool.

I know it’s a new pump but still need to verify it’s getting 120v to work.

But I would start by checking for 120v and if good move to the float switch error.
 

Storyteller12

Premium Member
Joined
Sep 3, 2022
Messages
20
Location
VA
most likely. Need to check at the main board to verify it’s not getting 120v. If the main board is reading 120v then it’s a bad wire/ connection.
 

Storyteller12

Premium Member
Joined
Sep 3, 2022
Messages
20
Location
VA
Just to clarify the control panel is the buttons to operate the dishwasher. I’m not referring to that. I’m talking The main control board which is the “brain” of the dishwasher.
 

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
I understand what you’re saying, I’ll do that and reach out with an update. Do you know why something like this could occur?
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
135,973
Location
Vicksburg Junction, Arizona
@Storyteller12 is right, The wash motor should be getting a constant 120 volts to it to make the wash motor run. Yes, its possibly the wash motor is defective right out of that box, that does happen from time to time.

Here is the wash motor assembly for your model: W11084656 Motor-Pump

You can use the safety pin trick if your meter leads are too big:

safety pin 500x250.jpg


Here's how I do it in this thread, and advise others to do it the same way:
dishwash120volts.jpg


Here's the main control board for your model:
Control Board W11305297


Jake
 

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
Just an update, decided to pull the board since I already had the door panel screws undone. From my initial thought, the panel is completely fine. Does anyone see any flaws on the board?
So if the board is fine, I should be looking at the wiring harness/test the motor to make sure it's receiving 120v?
 

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Storyteller12

Premium Member
Joined
Sep 3, 2022
Messages
20
Location
VA
i don’t see anything out of the ordinary. I’m guessing it’s a defective replacement motor as you said you hear a humming sound.

But a multimeter will confirm all this
 

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
I did notice on the board that my wiring harness is missing a connection to the red/yellow marked on the gray box holding the board. Thought that was wierd, off to test the motor. If it isn't the motor then would it be the wiring harness?
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
135,973
Location
Vicksburg Junction, Arizona
Yes I agree.

Jake
 

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
I ordered a new board. Thank you both for the help! Will give an update when new one is installed. With the board looking good, is it the fuse or capacitor that is restricting the 120v?
 

Kmillzz

Premium Member
Joined
Oct 6, 2022
Messages
9
Location
Northeast
I’m trying to understand why my circulation pump is not receiving the full 120v. I understand that I should replace my main control board (already bought) but why would my board not send the full 120v. I’ve checked the board for blown capacitors and the board looks mint. Is it the relays that are causing the decrease in voltage?
 

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Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
135,973
Location
Vicksburg Junction, Arizona
On your main control board in your photos of it above--->P5-2 and P5-1 is the voltage to the wash motor. It comes from the Pilot Relay and Motor Triac.

You can also disconnect power to the dishwasher and ohm test the wash motor itself, and you should read 5 to 15 ohms on it from those 2 wire connector pins that go to the wash motor.

Here's your tech. data sheet that shows you:
 

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