Check the electrical connection under the dishwasher, right behind the toe panel. Look for 120VAC between the black and white wires. Check to make sure there are no loose wires. For some reason, dishwasher connections have a tendancy to erode or easily loosen up and disconnect.

Please keep in mind that 120VAC is potentially lethal. It should never be approached without your clearest concentration. Never allow any bare wires to come into contact with each other, yourself, or the metal chassis of the appliance. Never touch a wire or a terminal, while any part of your body is touching metal or another wire. (Not meaning to scare you: Just be very deliberate and cautious)

With AC (Alternating Current), black and red are not important. Select the mode on your meter that corresponds to the 200 Volts AC. Your meter may say, "AC Volts", or it may just have a symbol. The wavy line is for AC; A straight line is for DC. Choose the wavy line for checking household volts.

The incoming power for your dishwasher is just behind the toe panel, usually protected by a small sheet metal box. The cover on the box is normally secured by a single hex-head screw. No need to remove any wire nuts from wires: just place one probe of your meter into the cap on the black wires; and the other probe in the cap on the white wires. You may need to wiggle the probes a little, to ensure the tips are in contact with the bare wires inside the caps.

You're looking for voltage close to 120. Also, make sure none of the wires is loose, or disconnected. If the connections are loose or disconnected, make sure you turn the dishwasher off at the breaker, before re-connecting them.