How to Replace Your LG Dishwasher’s Pump and Motor Assembly

July 20, 2018
Dishwasher Repair
Your dishwasher’s pump and motor assembly is the part that controls a lot of motion and water release. That means a lot can go wrong with the part over time, and there are different signs of problems. A broken pump and motor assembly can cause anything from a leak to a drainage issue. A bad motor might also be why your dishes aren’t getting clean.
If you want to replace the pump and motor assembly in your LG dishwasher yourself, order replacement part #AJH31248604. Then follow these steps:

1. Unplug the dishwasher and turn off the water supply.

You should always unplug a major appliance before any repair procedure. During this particular job, you will be disconnecting wires, removing drain hoses, and uninstalling the machine. It’s absolutely essential that you separate the appliance from its power source for your safety.
Also turn off the water supply line before you get started.

2. Uninstall the dishwasher.

First, remove the lower access panel and foam the sound dampening foam. Next, loosen the water connection line from the inlet valve. Also, unscrew the junction box cover plate and loosen the wires by unscrewing the wire nuts. Before you separate the wires, you can take a picture to use as a guide during reinstallation later.
Continue uninstalling the machine by disconnecting the drain hose from the garbage disposal and pushing it into the dishwasher side of the cabinet. Then open the dishwasher door and remove the mounting screws under the countertop.
Shorten the bottom legs so you have plenty of margin for removing the dishwasher. Then grab the sides of the machine and wiggle it out from the cabinet.

3. Remove the interior water guide.

Start by removing the upper and lower racks inside the machine. At the bottom of the interior space, pull the wash arm assembly out. Also remove the screw holding the water guide retaining clip next to the rear arm.
Next, start to remove the water guide. Loosen it from the retaining clips at the top of the interior, then the middle of the machine. You can fully remove it from the bottom by rotating it counterclockwise out of the filter assembly. Remove the whole part carefully and set it aside on a flat surface.

4. Remove the pump and motor assembly.

Close the door and tilt the machine down on its back panel. Make sure there’s plenty of space; setting down a towel or a blanket can also protect the back from damage and catch any excess moisture in the machine.
Once you can access the bottom, unscrew the bottom access plate. Set the plate aside.
Use pliers to loosen and release the clamps on the three hoses: the overflow, vent, and drain hoses. Then disconnect them.
Take a picture of the wire connectors around the pump and motor assembly to use as a guide later, then disconnect them. Next, unscrew the screw holding the ground wire flush against the assembly. Also unscrew the sump holders that secure the assembly in place.
Turn the machine upright. Reach under the machine to push in the tabs and pop the assembly up at the same time. This will shift the assembly from its mounting tabs. Once it’s loose, you can just open the door and reach into the dishwasher to remove the assembly.

5. Install the new pump and motor assembly.

Before you install the part, make sure the sump gasket, or the black seal around the edge, is firmly in place so the leaks won’t form around the edge. Then slide the assembly into the hole. Orient the part using the two arrows as a guide: one arrow is on the machine’s lip near the assembly cavity, and the other arrow will be on the second ring of the part. Once the arrows match up, firmly press the part down until you hear the click of the mounting tabs.
Shut the door and tilt the machine onto its back panel so you can secure the assembly from the bottom. First, put the sump holders in positions and hand tighten the screws as much as possible. Use a long-handled screwdriver to tighten them the rest of the way.
Next, you’ll reattach the wiring. Start by tightening the three grounding wires in place against the assembly. After that, start plugging the wire connectors into the new pump and motor assembly. Use the picture you took earlier to ensure all of the wires are in the correct position.
Then reattach the three hoses. Firmly push each of the overflow, vent, and drain hoses over their ports. Shift each of the clamps back into position. Once everything is tightened, put back the bottom access plate back into position and replace the screws.

6. Reassemble the machine.

Tilt the dishwasher back upright. Open the door and reinstall the water guide. First, put the bottom port of the water guide into the top of the pump and motor assembly, and rotate it clockwise. Next, snap the guide into place along the middle and top mounting mounting brackets. Then screw the retaining lip in place on the right of the water guide’s bottom portion.
Align the lower wash arm’s center with the top of the filter assembly and push it firmly in place until it clicks. Then reinsert the dish racks and shut the door.

7. Reinstall the machine.

Now that the machine is fully reassembled, you can start putting the appliance back in place. Many of the steps are simply the uninstallation steps working backward.
To start, make sure the dishwasher drain hose’s end is pushed through the cabinet so you can attach it back to the garbage disposal later. Also, wind the electrical supply line under the machine and through the junction box. If it’s difficult to reach, prop the right edge of the machine onto a wooden block to give yourself more more. Secure the electrical supply line with the strain relief nut once it’s through.
Next, push the dishwasher back into position under the sink. Lengthen the support legs if you shortened them during uninstallation, and attach the dishwasher with the underside of the countertop with the mounting screws.
Then attach the drain hose to the garbage disposal. Tighten the clamp and elevate the middle on a hook or support.
Go back to the junction box under the dishwasher. Reconnect the wires using the wire nuts and your previous picture as a guide. Then cover the junction box with the cover plate and screw it back in place.
Reconnect the water supply line to the inlet valve.
After that, add back the insulation and reattach the lower access panel.
Once you turn on the water, check for any leaks from gaps or loose connections. If there isn’t any sign of water, you can turn the power back on and use your newly repaired appliance.
For more appliance repair procedures and troubleshooting expertise, go to Flamingo Appliance Service. You can search for DIY repair steps or schedule a service call.

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