Dishwasher not filling properly?

[fell-like-rain]

The problem: dishes in bottom rack are not getting clean.

Observations: when opened mid-wash-cycle, the upper spray arm has clearly been working- water is dripping down from the top rack, and the dishes on the top rack are wet and getting clean. However, there is little/no water pooled in the base of the machine (where I'd expect an inch or two), and it seems like the lower dishes are only damp.

Hypothesis: The machine is not filling with water properly, and thus the bottom spray arm isn't working much/at all.

Steps taken so far:

• Cleaned filter
• ]Checked the float to make sure it moves freely
• Cleaned out drain hose
• Made sure spray arm holes aren't obstructed
• Made sure water supply lines aren't closed/kinked/obstructed

None of this has made much difference. At this point my best guess is it's some kind of pump or sensor issue, which may be above my pay grade. Any advice?

[lthenderson]

Was the lower spray arm working? There is a divertor valve that controls how much water is going to the upper and lower spray arms in a dishwasher.

Perhaps obvious, but are you using the right setting?

[sonofsven]

It could be the pump isn't strong enough to run water through the spray arms. On mine the pump still spun but the impeller was worn enough to cause it not to work.
Some of them have a ball in a tube that pushes water from one arm to another and this can get get gummed up.
Do a Google search of your brand and model and some key words about your problem and see if any of the results line up with your experience.

[BlueMR2]

Just had the pump replaced on mine due to odd noises and we found the impeller was missing, like gone, not there at all...  In the process we also found that the water valve for the feed was almost completely blocked.  Surprising that our dishes were getting clean at all...

[aasdfadsf]

It sounds like a problem with the recirculation pump. Whether that's an issue you'd want to take on yourself I couldn't say.

I had a similar problem once, and the guy I hired had diagnosed it but showed me some potentially expensive replacement parts he found quickly from googling it (he's an immigrant from Eastern Europe who was in an odd middle zone between being a professional and just a handy man). I found a much cheaper one with my superior google-fu and then paid him a fair price to replace it for me. It's worked great ever since.

Keep in mind that if this dishwasher is old enough, replacing the whole thing could be better.

[SmashYourSmartPhone]

Keep in mind that if this dishwasher is old enough, replacing the whole thing could be better.

Yesss... this is the way!  Ending is better than mending, as we all know... you wouldn't want to be seen as the kind of person who uses an obsolete dishwasher, would you?  Think of what they'll say about you...

You said you checked the supply lines for kinks, but did you check the inlet valve?

Shut water off to the dishwasher, pull the kickplate, and you should be able to find the inlet valve.  If the dishwasher isn't filling properly, either that's clogged, bad, or isn't getting proper power.

Remove it, see if there's a inlet screen on it.  If so, pull that out and clean it out.

You can also check to see if it's getting a clean 120VAC on the pins while running.  Various wiring faults can lead to that valve not getting enough voltage/current to operate, and if you measure the drop across it while it should be open, you can tell if there's a wiring fault somewhere in the dishwasher that needs to be addressed (I believe the handle cutoff switch is often a problem).

If it's not clogged, and it's getting a full 120VAC, replace the fill valve.  They can go bad and stop working properly.  It'd be easy enough to hook a bit of spare tube to the end, pull it out from the dishwasher, and start a cycle to see if you get good flow.

Otherwise, keep troubleshooting.  But your problems seem consistent with a bad or improperly operating fill valve.

[zolotiyeruki]

If the dishes in the bottom rack aren't getting clean, but the ones in the top rack *are*, then I'm disinclined to think it's a fill valve problem.  My dishwasher also doesn't have a ton of water in the bottom while it's washing.  You can thank the US DoE for that one. There are other possibilities:
1) the piping to the lower wash arm is clogged/blocked in some way
2) the holes on the wash arm (either one!) could be clogged, so water doesn't hit everything
3) the holes on the wash arms which make them spin are clogged, so they don't turn and hit all the dishes
4) there's some other malfunction of the wash arm that prevents it from spinning.  Our dishwasher's wash arm recently split along its side seam, so much of its water was gushing out sideways (and running out the front of the dishwasher) instead of hitting the dishes

When our dishwasher most recently started misbehaving, I bought a second-hand knock-off Action Cam (i.e. GoPro) and stuck it in a mostly-empty dishwasher with a waterproof work light.  Ran a cycle, pulled it out and watched the footage, and was able to diagnose the issue immediately.

IMO, dishwashers need to have transparent doors.

[BlueMR2]

Keep in mind that if this dishwasher is old enough, replacing the whole thing could be better.

If you're in that range though, plan on extra expenses.  So, it turns out that counter heights have changed over the years.  If you've got an old dishwasher and go to buy a new one it may not even fit.  You may also be looking at a partial kitchen remodel.  That came to light while I was having this one fixed while I had considered replacing it...