How to test the diverter motor (no disassembly yet). The diverter’s job is to switch water flow between:
- Lower spray arm
- Middle arm
- Upper arm
- Sometimes a dedicated zone
If the lower arm never moves, the diverter is the prime suspect.
You can confirm it without removing anything.
Test 1: Door-open rotation check (most important)
Goal: See if the diverter ever sends water to the lower arm.
- Start a normal wash cycle with dishes removed.
- Let it run 3 minutes.
- Open the door quickly (don’t wait for pump to ramp down).
- Look at the position of the lower spray arm.
- Close the door and let it run another 4 minutes.
- Open again and check the arm position.
Interpretation:
- If arm never changes position at ANY time: Diverter is stuck in one zone (typically upper arm).
- If arm moves at least once: Diverter is functioning at least partially. Fault may be pump, filter, or pressure related.
- If movement is random but weak: Diverter may be slipping internally (gear partially stripped).
For a definite diverter failure, you’ll see upper arm spraying strongly, lower arm not at all, and static lower arm across multiple checks.
Test 2: Listen for diverter rotation
The diverter motor “indexes” at set intervals. You can hear it.
What to do:
- Start a cycle.
- Stand in front of the dishwasher during the first 10 minutes.
- You should hear a faint:
- click-click
- whirr
- short hum for 3 seconds
If you hear nothing — especially no periodic hum — the diverter motor is not being driven or is mechanically jammed.
If you hear repetitive ticking, the diverter is trying and the internal gear is stripped (common for this generation).
Test 3: Real water-pressure test (tells you 100 percent if the diverter is indexing)
Do this with a cup or small glass.
- Start a cycle.
- After 3 minutes, open the door.
- Observe which spray arm is wet and dripping:
- If upper arm only is wet: diverter is stuck in upper zone.
- If lower arm never gets wet after multiple openings: diverter jammed.
- If sometimes middle arm gets wet, sometimes upper, but never lower: partial indexing failure.
How it actually went down:
My KitchenAid dishwasher has been a solid, quiet, low-maintenance unit for about eight years, but this is now the second major part to fail.
The first failure was four years ago when the self-cleaning pump mesh tore apart. The extended warranty covered everything, and I definitely got my money’s worth.
This time the diverter assembly died. The diverter controls where the water goes. Top, middle, or bottom spray arms.
I ran the symptoms through ChatGPT, followed its diagnostic checklist, and it pointed straight at the diverter motor.
Steps:
- Power off at the breaker
- Remove racks and spray arms
- Disconnect supply line
- Pull out dishwasher
- Replace diverter assembly
- Reassemble everything
After putting it back together I spotted a slow drip on the old supply line. It was eight years old anyway, so I grabbed a new one from Home Depot.
Back home, I pulled the dishwasher out again, swapped the line, levelled it, and started reassembling. Then I dropped the tiny washer from the supply line underneath the unit. Metal coat hanger to the rescue. Fished it out, reattached the line, and verified no leaks.
Breaker on. Test cycle running. Open after two minutes. Lower spray arm not moving. Wait a few more minutes, open again. It moved. Problem solved.
Levelled the unit one last time and put the trim back in place.
The garbage pile is now one dead diverter assembly and one old supply line.
Total cost was about two hundred twenty five dollars plus tax for parts. A technician would have likely charged two hours of labour on top.

