Whirlpool dishwasher won't run

Dishwasher Repair
1

After completing the last cycle fully, the machine won’t run any more. I checked the door switch and it had continuity and voltage running into the tan and red wires. I also checked the TCU fuse and its fine (continuity and voltage present). However, when I trigger the door switch, the voltage drops to zero.

What should I be checking next to troubleshoot the inability to start the machine?

Thanks.

2

Here are the parts
Replacement parts for WHIRLPOOL DU620PWKQ0 | AppliancePartsPros.com

Here a couple tech sheets
https://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%208275305.pdf
https://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%208533345.pdf

[COLOR=Blue]However, when I trigger the door switch, the voltage drops to zero.[/COLOR]
Not sure what this means, where are your meter leads connected?
Also I do not see a red wire on the diagrams.
Both switches must close to get power to the board.
I would measure the voltage at the board (P7 white/violet to P8 tan).

3

Thanks for the charts.

I measured the voltage on the door switch on the metal where the wires touch the interrupter. I meant to say I used the black / tan wires. Now, I will check on the P7/P8 terminals and let you know.

4

I checked the voltage on P7/P8. When the door is open, there is no voltage (as expected). When the door switch is triggered, I read 2.6V AC.

Is this voltage right? What do I check next? Thanks.

5

No, you should see line voltage 120 volts AC approx.

Sounds like one of your door switches is not closing or the thermal fuse is blown.

Unplug or remove power from the machine.

Remove the thermal cutout and measure across it, should be 0 ohms.

Remove one wire from the switch or the plug to the switch.
Measure across the switch
Actuate the switch it should go to 0 ohms

Then do the other one.

6

I checked both the thermal cutout and both switches. The cutout read 0 ohms as did the switches when activated.

The switch read 90V on the black/tan lines prior to killing the power and prior to activation when it drops to 0V.

Any suggestions on how to proceed? Thanks.

7

Check the power going into the unit and the connections.

90 volts is way too low.

8

I checked the power coming into the junction box under the machine and it is at 120V. The wires are properly twisted together behind the plastic wire nuts and the ground is attached.

Where to check next? Thanks.

9

The strange voltage you saw earlier would indicate that you may have a problem with the wires going from the line connection point up to the switches/board etc.

I would check from the tan on the one switch to the white/violet on the other switch. With both switches closed you should get 120 volts.

if OK
I would go back and recheck this.
I would measure the voltage at the board (P7 white/violet to P8 tan).
Also should be 120 volts.