Hi, my name is ***** ***** I have been in the home improvement and repair field for 20 years. I will be very glad to help you today. First turn the water supply off and remove the panel on the front on the bottom. Have some rags ready and disconnect the water supply. Direct the water supply into a bucket and turn the water on a little bit to confirm there is not a supply issue. If you confirm that there is water there then the water valve is the issue. The water valve is what the supply is connected to. It is held on by a couple screws. Be sure to turn the power off before removing the water valve. Once you have removed the anchor screws, pull the valve out and loosen the hose clamp and disconnect at the push connector. Order a new one from the model number and the numbers on the valve. The best is to order from a local appliance parts store. They may even stock the part!
Do you have to take door off first or is it at the back
Neither. The access is in the front at the bottom. There are two screws holding the panel on. It is accessible without removing the dishwasher and without removing the door.