Ah, the good old days when dishes were washed and dried by hand. Yeah, right! Next to the TV and the microwave, the dishwasher is probably the most used modern appliance there is. And, as with these other contraptions, the day it breaks down is memorable. So let's call a meeting of the Fix-It Club to figure out what dishwashers do—and how to keep them doing it.
A dishwasher is a major appliance designed to clean dishes, silverware, pots and pans, and other kitchenware. It delivers water through the water inlet into the tub while the detergent dispenser releases detergent in stages to clean the dishes. The heating element warms the solution and a pump channels the water to spray arms that spray and clean the dishes. When the wash cycle is complete, clean water is sprayed to rinse off the detergent. The heating element is also used to dry dishes. Some dishwashers have upper and lower spraying arms while others have a single arm. Also, some dishwashers have a dispenser that adds a rinsing agent to the rinse water.
Built-in dishwashers are installed under countertops with permanent wiring and plumbing connections. Portable models have a flexible coupler that connects to the sink faucet and a drain tube that runs through the sink drain. Power is supplied through a 120-volt plug.
Before working on a dishwasher, always turn off power to the machine. Built-in models are plugged in under the sink. If you can't easily access the plug, turn off the appropriate breaker in the electrical service panel. Also remember to locate the water supply shutoff and turn the water off before beginning repairs.
Access dishwasher controls:
Unplug the dishwasher or turn off power at the electrical service panel.
Remove retaining screws on the interior door and on the front of the control panel, then remove the interior door panel.
Remove the control panel cover by removing clips that secure the cover to the door.
As needed, also remove retaining screws to remove the lower front panel and expose the controls.
Test a dishwasher heating element:
During the unit's first cycle, open the door and measure the water temperature with a meat or candy thermometer. If it is below 140 degrees F, test the element.
Before working on the heating element, unplug the dishwasher or turn off power at the Electrical Service Panel.
Use a multimeter set to RX1 (resistance times 1) to test the heating element. Look for a reading other than infinity. Also place one probe on a terminal and the other on the element's metal sheath to check for continuity to ground (not good!).Replace an element that fails either test.
Unplug the dishwasher or shut off power at the electrical service panel.
Remove the lower front panel and manually turn the motor fan blades. If they don't move freely, look for obstructions or call for service.
Disconnect the motor wires from their terminals.
Set a multimeter to RX1 (resistance times 1) and attach a probe to each motor wire terminal. The motor should show little resistance.
Check the ground connection by placing one probe on the bare metal housing of the motor and the other probe on each terminal in turn. There should be no reading. If the motor fails either test (in steps 4 and 5), call for professional service.