Shift to upper spray arm does not happen

Dishwasher Repair
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1

Steps taken:

  • checked water temperature
  • checked rinse agent
  • checked sump & filters
  • replaced pump assembly
  • tried ‘door crack’ trick, successfully shifting to upper spray arm
  • ran self-test, successfully shifting to upper spray arm
  • added 2 gallons of water after filling. This did not cause the shift to happen

Observation: the ‘shift to upper spray arm’ pause during the normal cycle is not long enough to shift to the upper spray arm.

Having read the posts in this forum, (and having fixed the machine in my previous residence by doing so) I’ve recently replaced the pump assembly in my dishwasher to address the “top rack doesn’t clean” problem. This time it didn’t help.

According to detailed posts elsewhere and verified by experiment, the switch between lower spray and upper spray is controlled by a pause in the cycle. A short pause switches from lower to upper, and a long pause switches from upper to lower.

If I simulate the short pause by cracking the door for 1/2 a second, the machine successfully switches from the lower spray arm to the upper spray arms. I can hear the difference and see the results when washing.

Unfortunately, when running a regular cycle without helping it along, the documented 0.4 second pause that I hear is not long enough to successfully switch to the upper spray arms.

Any ideas on a fix?

2

Problem: Upper spray arm doesn’t “work”

Observations: Pump OK, water level OK, no blockages

Theory as to the real problem: The program timing is off, so even though everything is mechanically fine, the programmed shift fails. A replacement control board might or might not fix the problem, but it’s doubtful.

The fix: Just remove the check-ball. Save it just in case someone comes up with a fix for the bad-program-timing problem.

Possible downside: dishes might not get REALLY clean, as the spray power is now split between upper and lower.

Result: Dishes came out pretty clean anyway – and on both racks.
Total parts cost $0.
Total time of repair: 5 minutes.