Dishwasher would not drain every time

First turn the power off! If you have water in the tub, use something like a wet/dry shop vac to drain as much water out as possible. Removing the strainers will help get more out. To remove the smaller horseshoe shaped strainer, pull up and towards the handle. The sprayer is then removed by rotating the base of it slightly. Then you can remove the large strainer. The more water you get out the better! Then remove the kick panel. You will see the drain pump right in front of you with a white and a purple wire. Disconnect the wires by pulling their tabs towards you, and move them out of the way. With a screwdriver, loosen the worm clamp on top of the pump that connects the drain line to the pump. Have a towel handy, even if you got all of the water out, there will still be some in the line. Then take a pair of pliars (long nose may work best, or small channel locks) and compress the clamp on the black hose behind the pump, moving the clamp towards the center of the hose. The pump should now move a little. Pulling the pump towards you, wiggle slightly to try to remove the pump from its support, preferably without breaking the tabs, but keeping them intact is not critical if you are replacing the pump. More water may come out at this point, so be prepaired. Put the new pump in by reversing the process, making sure you do not break the support tabs. Slide the compression clamp into place. Reconnect and tighten the drain line, reconnect the white and purple wires. Dry your work area carefully so you can spot any leaks. Apply power, and run a rinse cycle, watching for leaks. If everything looks ok, kill the power again and reattach the kick plate. Turn power back on one last time, and enjoy your dishwasher again!