The Call
A customer in Hallandale Beach called us with two complaints about their Whirlpool dishwasher: water was leaking from under the unit during the wash cycle, and the dishes were coming out wet — the heat dry function had stopped working entirely. Both issues had started around the same time, which is a familiar pattern we recognize immediately.
Two symptoms appearing together — a leak and a sudden loss of heat drying — almost always point to the diverter assembly. The leak comes from a worn rubber o-ring on the diverter shaft. The missing heat dry is not a heater failure at all — it is a built-in Whirlpool safety response to something going wrong during the cycle.
Diagnosis
Confirmed the leak source
Ran a short wash cycle and observed the leak location — water was escaping from under the tub at the sump area, not from the door seal or supply line. This immediately pointed to the diverter shaft o-ring, which seals the shaft where it passes through the bottom of the sump assembly.
Accessed the diverter assembly
Pulled the dishwasher out and removed the lower access panel. Inspected the diverter shaft o-ring — the rubber had hardened and cracked, breaking the seal under wash pressure. Also inspected the diverter motor: contacts showed moisture damage consistent with the o-ring having leaked over time. Both parts were flagged for replacement.
Read error codes from control board memory
Connected to the diagnostic mode and confirmed stored fault codes related to the diverter position and cycle interruption — exactly what we expected. These codes had triggered the control board's safety logic to disable the heating element. The heater tested good electrically; it had simply been shut off by the board.
The Repair
The diverter shaft o-ring and diverter motor are a common failure pair on Whirlpool-platform dishwashers — the same assembly is shared across Whirlpool, KitchenAid, Maytag, and Amana dishwasher models. We keep both parts in the van. The o-ring was replaced, the diverter motor was swapped, and the sump area was dried and inspected to confirm no residual damage.
With the mechanical repair complete, we ran the full diagnostic cycle. This cleared the stored fault codes from the control board memory and restored normal heater operation. A post-repair test cycle confirmed no leak, full wash pressure, and heat dry functioning normally. Total time on site: 45 minutes, one visit.
Why the Diverter O-Ring Fails — and Why It Takes the Heater With It
The diverter on a Whirlpool dishwasher sits at the bottom of the sump and controls which spray arm receives water pressure during the wash cycle — alternating between lower and upper arms. The shaft that actuates this valve is sealed to the sump wall by a rubber o-ring. Over time, the combination of hot water, detergent chemistry, and thermal cycling degrades the rubber. The o-ring hardens, loses its compression, and eventually cracks — allowing pressurized wash water to escape around the shaft.
Once water reaches the diverter motor — which sits just below — the moisture damages the motor contacts and can trigger position-sensor faults. The control board detects these faults mid-cycle, logs the error, and shuts off the heater as a safety precaution. By the time the customer notices their dishes are not drying, the original cause was the o-ring failing weeks earlier.