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Parts for GE ZBD0710N20SS Dishwasher - AppliancePartsPros.com

Click on the below picture to get more info on the detergent dipense (includes a Q&A and a video.

Remove power from the unit
Check the wires going from the dispenser up to the control board just to be sure they are OK.
Open the unit up and the two wires from the dispenser.
Measure across the wax motor with a meter.
Should be around 1,000 to 2,000 ohms.
If infinite ohms replace the dispenser.
Note that I do not have access to GE tech data so am guessing the resistance value.
If infinite ohms then replace the dispenser.

Try to manually push the door actuator (not the wax motor plunger) to see if it will open.
If not I would replace the dispenser.

FYI: The way the wax motor works is that there is wax at the back of the plunger. When power is applied the wax melts and expands. This then pushed the plunger out.

You could hook the wax motor to a line cord and then plug it in to see if it works. I would not try this unless you have experience doing this type of stuff.

If the dispenser is OK then the control board is probably bad.

Part number: AP3767572