Gene, I have a SHU66C05UC/14.
My soap dispenser won't open, either. I have cleaned it, inspected it. It slides to close and locks nicely. When I pop the blue tap with my finger, it cleanly snaps open and up. Nicely. So while I could see replacing the dispenser unit... is the unit really my problem, or is it what actuates the unit to snap open? Today, the technician came while I was at work. The unit is under warranty, and the service fellow talked my wife into 'just pouring the powdered detergent into the machine, and not fixing the dispenser. Whooey! How can one test the actuator?

I had a similar problem where the soap packets would turn into a gooey mess and remain stuck in the dispenser.

After much research, I stumbled across a description of the function of the wax motor. Based on the description, I came to the conclusion that the motor/actuator system that operates the soap dispenser, ALSO activates the rinse. OR - another way of saying it would be that the FIRST time the motor is activated, it dispenses soap. The SECOND time the motor is activated, it dispenses rinse.

What would happen if you were to interrupt the dishwasher AFTER the soap was dispensed and BEFORE the rinse.

I ran an empty cycle for about 20 - 30 minutes ... interrupted the cycle ... then ran it again.

Yeah ... the problem was fixed and it has been working flawlessly for about a month now.

BEFORE you spend a bunch of money on parts and the labor to replace the unit, try this "free" approach. I hope it works for you like it did for me.

Basic tests.....find the tech sheet on how to do a diagnostic on bottom panel or behind main panel........Take off front panel........try and manually trigger the door open if you can push the tab and it pops open easily that's a good sign thus far.......ohm the dispenser motor out make sure it's a complete circuit if it's not you have a bad soap dispenser and replace the whole thing don't just try and replace the wax motors on them they break all the time.....before you but a new dispenser though test to make sure you have 120v going to it from the main board run a diagnostic mode and it may take up to 7-10 before the dispenser opens up depending on model your tech sheet should tell you.....within your time frame on the grid you should have 120v going to the dispenser if you don't then more then likely you have a main board possibly going out.....also to remedy this whole situation and not pay for any parts you can just wait till the water fills up inside the unit and once it does and starts splashing around open the door and add the detergent right in there kablam no parts necessary! If you'd rather pay a tech 100-150 to come out to your house to install this we'd be glad to help lol......