Gotta say, I love your videos, they are so valuable to the industry. I recently got promoted to manager, and I've been adding videos to a playlist that I share with my technicians for whenever they have any questions or want to better themselves before they see an issue in the field. The information from your channel is priceless!
Sounds like the motor is locked or is bad if the dishwasher comes with a schematics tech sheet see if you can preform a diagnostic it should be on the tech sheet and then you can test the components individually
Depending on the type of dishwasher, might also be a blocked circulation pump. If it fills but never spins, it could be that. Real common in Electrolux/Frigidaire but I've seen it in Amana/Whirlpool too