I've got a 15 year old Kitchen aid that has performed well for years but performance has suddenly taken a nose dive. :(

Checking it out, the top spray doesn't seem to be working at all (some water comes out, it doesn't spin, and remains in the starting position even after all the cycles. Moving it manually shows it spins freely. I checked the Delivery tube for upper spray arm as it had cracked in the past but it was fine, and no issues with seal. It just seems like the upper arm isn't getting enough water.

So I started checking the pump. I removed the fine strainer (#14 Pump Outlet) and it's fine, only minor buildup along edges. I was able to remove the impeller without trouble and it too was fine. I also removed #9 (Box Separater) and inspected the chopper, again all looked good. The check ball seems free and without buildup. I didn't pull out the drain impeller as I wasn't sure at what point I needed to heed the dire warnings on the pump diagram about replacing the "pump gasket and retainer" or where I might find the need to buy and use the centering tool. Are these included in the combo Drain & Wash impeller kit (gasket and retainer)? If not, which parts are they? I'm assuming none are needed until I remove #25, the pump base.

So after reading through other posts, it looks like I need to verify the amount of water delivery. Nothing's changed in the supply hose and pressure, but what is the amount of water that needs to be delivered? water flows in ok, but it does look a bit on the low side. I added more to the bottom, but only just read the open door trick to force the upper arm so I don't know if that would do it. I'm guessing that for all operations, the float should be lifted? I've been using the rinse-only cycle for testing since that doesn't go into a water heating mode, but I don't know if that cycle uses less water. Water does enter the system at a pretty good rate, but I'm not sure how fast it needs to be or how much total.

So some questions for the pros.

1. Does it seem I'm chasing the right leads?
2. How much water (and what's the fill time) should be delivered?
3. What's the cycle timing for switching the upper arms vs lower arms? Does it apply to Rinse Only cycle?
4. I noticed that someone posted a link in another thread to the Secured Whirlpool site with a Service and Troubleshooting manual. Is there one for this model? That would really help.

Thanks in advance!

Still looking for some help, especially if someone has the service manual. More updates:

I replaced the inlet valve. Now water is flowing in much faster and the water level rises almost to the overflow cutoff point. Interestingly, now it doesn't seem to enter the heating cycle. Both Pots and Pans and "normal" cycle stall after filling. Gentle/glassware cycle doesn't seem to heat and just goes straight into wash mode. Service manual would help to determine what the two cycles are apparently so different.

Top spray arm still isn't spinning. In looking at this model, the pump drives both the lower and upper arms at the same time due to a diverter at the impeller discharge (about 1/6 the water flow goes into a separate path back into the housing and then up to the top arm). Everything seems clear so any advise or suggestions on how to fix the problem would be appreciated.

I'm glad it helped. I'm still hopeful someone might have some guidance on why the heating unit seems to have suddenly stopped working now that I've fixed the water flow issue. I had been adding hot water (boiling from the stove as makeup water. Hopefully the extra hot water into the 25% full dishwasher didn't damage anything. Is there a thermal breaker on the thermostat that needs a manual reset? And I've still got the problem of seemingly not enough flow to make the top spray arm rotate :(

Thanks. Just the info I was hoping for. I'll take a look this weekend.

[COLOR="Blue"]Do they overheat with low water and break?[/COLOR]
They should not because they are also used to dry the dishes when there is no water in the unit

[COLOR="Blue"]I'm getting 3.1 ohms for RUN, and 6.0 for the WASH & DRAIN Mode.[/COLOR]
The Run does seem a little high but I cannot say if it is actually causing a problem. I have no info on how tight the spec is.
[COLOR="Blue"]
It's a 15 year old unit so I'm wondering if I just need to bite the bullet and get a new one.[/COLOR]
It sounds like you have done a thorough job checking everything mechanical so all that is left is the motor and that is obsolete. Therefore a new unit is your only option.

[COLOR="Blue"]Recommendations welcome for a good unit[/COLOR]
I do not have a recommendation but I would get one with the controls on the front. I am not a big fan of units with the controls on the top of the door.
Also I would not buy a unit with lots of extras like a tank for detergent that you only fill every week or so. The more auto stuff they add the more things that can go bad.