Soap dispenser does not open every time

SOURCE: diswasher not rinsing properly

You may have a clogged wash pump, resulting in low water pressure. This may not be enough to drive both spray arms at the same time. This can also be causing the problem with your detergents not being distributed properly. An easy way to tell if you have good water pressure is to open the door slightly while its in mid cycle. Look for a good strong spraying action from both spray arms. If you're not getting enough water, and you've already checked your supply hose coming in, then suspect you might have an obstruction somewhere. Most cleaning problems can be attributed to something as simple as food particles stuck in the vicinity of the wash pump inlet. You will have to remove the lower spray arm and coarse screen to get to it, however. Rule of thumb: If you still have to chew it, then it shouldn't go through the dishwasher. Scrape your plates of food particles, yes. But, don't put things like meat scraps, popcorn kernels, chicken bones, orange or lemon seeds, beans (the skins can clog the drain screen), etc. This does not mean you have to pre-wash BEFORE you wash. Most dishwasher detergents require the oils in foods to help activate the cleaning agents. One more thing: City water - stick with liquids or gels. Well water - stick with powders. Now, if all else fails ad you've checked the inlet to the pump and it's clear, you may have a bad drive motor and pump. Go with the cheaper solution, first. I hope this helps you. Let me know if I can help you any further.

SOURCE: Dishsoap stays in soap dispenser

Same thing happened to us. We noticed that it happened if the soap was left sitting before starting the washer. Since then, we immediately start the washer after putting soap in it and the problem appears to have gone away.

So much for the delayed start features, but at least the soap doesn't stick anymore.

good luck!

SOURCE: i have a kenmore dishwasher.

disasemble the pump housing and remove the debris that are located in the housing, not enough pump pressure to spin the spray arms to desolve the detergent

SOURCE: Whirlpool Gold Quiet Partner IV issue with soap dispenser

I'd check the spray arms it may be there is not enough water or the wataer is not getting where it needs to be to disperse the soap. that is where I'd start.

SOURCE: After the dishwasher runs there is a lot of soap

With the LG LDF6810 model, this is not a common problem. Please try the following test, With and empty dishwasher, add a small to normal amount of dry dishwasher powder and run an (empty) load.
Check to see if any soap remains in the dispenser cup.
If any remains, here are three things to do: 1.) Upgrade your dishwasher detergent to a name brand powder (e.g.: Electrosol or Cascade)
2.) When you load the dishwasher, do not place large items in the front, near the door/soap dispenser.
3.) Before you load the dirty dishes for the next several loads, with your hand, turn both the upper and lower wash arms so they point at the door. Load as you normally do and push the racks fully in. Before you close the door, spin both the upper and lower arms and confirm that they spin freely and neither hits anything. if either does not spin freely, pull out the rack and arrange so the arms can spin freely.
I find that the only time I have left over detergent powder is when the wash arms do not spin freely.
This is a common problem on most every energy star/water conserving dishwashers.
Please report back what you find, OK?