Whirlpool Dishwasher Not Cleaning Dishes Properly — 4 Diverter Motor Causes & How to Fix

You unload the dishwasher and half your plates still have crusty bits stuck to them. The top rack looks barely touched while the bottom rack is spotless. Or maybe it's the opposite — your bottom dishes come out with dried food while the top rack is clean. This inconsistent cleaning pattern isn't random. It's usually your diverter motor failing to redirect water between the upper and lower spray arms.

The diverter motor (part W10537869) controls water distribution in Whirlpool, KitchenAid, Maytag, Kenmore, and Jenn-Air dishwashers. When it fails, one spray arm gets all the water while the other gets barely a trickle. You'll burn through detergent pods wondering why nothing's getting clean.

Quick Symptom Check — Is Your Diverter Motor Failing?

Check these symptoms on your dishwasher. If you've got two or more, your diverter motor is likely the culprit:

• Top rack dishes come out dirty — plates have food residue, glasses are cloudy
• Bottom rack won't clean properly — pots and pans need hand-washing after the cycle
• Inconsistent cleaning cycle to cycle — sometimes top is clean, sometimes bottom
• No water spraying from one arm — spin the arms by hand, only one gets wet inside
• Humming noise during wash — motor is trying to move but physically stuck
• Water pooling at bottom — not draining completely, possible leak underneath

Cause #1: Diverter Motor Completely Failed (Probability: 65%)

The diverter motor itself burns out after years of switching water flow back and forth. Models like the WDTA50SAHZ0, WDT970SAHZ0, and WDT780SAEM2 are especially prone to this around the 4-6 year mark.

How to diagnose: Start a wash cycle and open the door mid-cycle (it'll pause automatically on most models). Check if both spray arms are spinning. If only one arm is getting water pressure, your diverter is stuck in one position. The motor has power but won't move.

Run your hand under the spray arms during a pause — you should feel strong water flow alternating between upper and lower. If water only comes from one direction throughout the entire cycle, the motor's dead.

Fix: Replace the W10537869 diverter motor. It's located at the bottom of the tub, accessible from inside the dishwasher after removing the lower rack and spray arm. Unplug the dishwasher and shut off the water supply first. The motor unclips from the sump assembly — no special tools needed beyond a screwdriver.

Part cost: $66.99 for OEM replacement
DIY time: 45-60 minutes
Difficulty: Moderate — requires removing internal components but straightforward

Cause #2: Diverter Disc Cracked or Warped (Probability: 20%)

The diverter motor moves a plastic disc that redirects water flow. Hard water deposits can warp this disc, or it can crack from thermal stress. Even if the motor works, a damaged disc won't seal properly — water goes everywhere instead of where it's supposed to go.

How to diagnose: You'll need to pull the lower spray arm and look down into the sump area. Shine a flashlight and look for the white or gray circular disc. If you see cracks, calcium buildup, or the disc sits crooked, that's your problem.

A warped disc will cause leaking at the bottom of the tub because water escapes around the seal. Check for water pooling under the filter area after a cycle.

Fix: The disc is part of the W10537869 assembly — you can't buy it separately. You're replacing the entire diverter motor unit. Wear work gloves when handling the old part; the edges can be sharp from mineral deposits.

Prevention tip: Run a dishwasher cleaner monthly if you've got hard water. Those white deposits absolutely destroy diverter components.

Cause #3: Wiring Harness Corroded (Probability: 10%)

The diverter motor connects to your dishwasher's control board via a wire harness. If you've had any leaks in the past, moisture gets into these connections and corrodes them. The motor itself is fine — it's just not getting the signal to switch.

How to diagnose: Pull the dishwasher out from the counter and remove the lower access panel (usually 4-6 screws along the bottom front). Look for the wire harness plugged into the diverter motor. Check for:

• Green corrosion on connector pins
• White crusty buildup (mineral deposits from water)
• Loose or disconnected wires
• Burn marks around the connector

Fix: If it's just corrosion, disconnect the harness and clean the pins with electrical contact cleaner. If the connector itself is melted or severely corroded, you'll need a new wire harness (and probably the diverter motor since they usually fail together).

Cause #4: Control Board Sending Wrong Signals (Probability: 5%)

Least common but most expensive. Your control board tells the diverter motor when to switch between spray arms. If the board's logic circuits fail, the motor gets confused signals or no signal at all.

How to diagnose: This is a process of elimination. If you've replaced the diverter motor and still have the same cleaning problems, the control board is likely the issue. Also check if you're getting other weird symptoms — random error codes, cycles that won't start, or the dishwasher stopping mid-cycle.

Some models like the KDTE204DSS0 and KUDS01FLSS6 have known control board issues that affect multiple functions.

Fix: Replace the main control board. This isn't a DIY job unless you're comfortable working with electronics and have a multimeter to test voltage. Most folks call a pro for this one.

Cost: $200-400 for the board plus $150-200 labor

When to Call a Pro

Replace the diverter motor yourself if you're reasonably handy. It's a straightforward swap on most Whirlpool-family dishwashers. You'll save $150-200 in labor.

Call a technician if:

• You've replaced the diverter motor and still have cleaning problems
• You're seeing multiple error codes on the display
• Water is actively leaking during operation (could be a pump seal issue, not the diverter)
• Your dishwasher is less than 2 years old and under warranty — let the manufacturer handle it

Honest assessment: if your dishwasher is over 10 years old and you're facing a control board replacement, put that $400-600 toward a new dishwasher instead. A diverter motor at year 6-8? Worth fixing.

Frequently Asked Questions

How long does a dishwasher diverter motor last?

Most diverter motors last 5-8 years depending on usage. If you run your dishwasher daily, expect the motor to fail closer to year 5. Hard water accelerates wear significantly — those mineral deposits act like sandpaper on the moving parts.

Can I just clean my spray arms instead of replacing the diverter motor?

Clean the spray arms first — pull them off and rinse out any food debris clogging the holes. But if one entire rack (top or bottom) consistently doesn't clean, that's a water distribution problem, not a clogged spray arm. The diverter motor controls which arm gets water pressure. Cleaning won't fix a motor that's stuck in one position.

Will the wrong detergent cause uneven cleaning like a bad diverter motor?

Wrong detergent causes film or spots on all dishes, not a pattern where one rack is clean and the other isn't. That specific pattern — top rack dirty, bottom rack clean (or vice versa) — is almost always the diverter motor failing to alternate water flow. Try switching detergents if everything's dirty. Replace the diverter if there's a clear pattern to which dishes don't clean.