Open the door and pull out the lower loading tray from inside the Haier dishwasher to clean contaminants stuck inside the grooves that the tray rides in, which can cause the dishes to be washed unevenly. Wipe the grooves on each side inside the dishwasher with a water-moistened paper towel. Wipe the wheels on the bottom of the lower loading tray as well. Slide the tray back in and confirm that it lies level.
Pull the lower tray out of the dishwasher to access the washing arm at the bottom, which can become stuck due to loose food and other contaminants clogging the hole the arm sits in. Lift the washer arm up and wipe beneath with a water-moistened paper towel. Wipe a water-moistened cotton swab around the rim of the hole. Push the arm back into the hole and the tray back into the dishwasher.
Put on kitchen gloves and run hot water to use to dissolve old detergent stuck to the inside of the detergent-compartment lid, which can prevent the compartment from opening during the wash cycle. Saturate a sponge in the hot water and wash both sides of the lid and the inside of the compartment. Allow to air-dry.