Lately, over the past several months, one thing that has been consistent is that people are not happy with their dishwashers and want them fixed. I've been seeing leaking pumps, inlet valves that drain water into the machine even when it isn't running, as well as broken hinges, a few busted springs, and other maladies. However, the most common complaint is that "my dishes aren't clean."
I'm going to tell you straight up that the overwhelming majority of complaints have nothing to do with the machine itself. Unless you have a wash arm that's broken or a clogged filter, the fact is that you will be spending money on a service call for this same advice, and maybe what you can do yourself. I'm a DIYer too, although I'm learning the value of a good professional for some repairs.
To date, I fix appliances for a living, and can say that I've have a few times the machine was actually "at fault". These are commonly a broken wash arm, where it doesn't spray or move properly, a dirty screen as many new dishwashers use a filter that needs to be cleaned out regularly, much like a lint screen, or this is clogged with minerals or torn. The pump can also rarely cause a problem. Don't get me wrong, it isn't a bad idea to have a pro look at it. We can find problems and let you know whether or not to put money or effort into same. Nevertheless, it's still a good idea to save money on a service call as long as you're sure this machine isn't leaking underneath. If you're handy, you check this too, but I digress. Here is what you need to do...
If you're getting a white film on your dishes, this is never the fault of the machine. This is your water quality and something you need to address soon. This is lime or calcium in the water, and it will deposit on your dishes the first time you use it if the water is hard enough. If you don't have a water softener, get your water tested and if necessary install a water softener. Don't fall for these electronic gadgets either, get an ion exchange that uses either salt or Potassium Chloride. These will keep scale out of your water heater, washer, ice maker, pipes and your dishwasher. You can try some of the drop in remedies in your machine or a different brand of detergent, but I would still suggest a water softener. Yes, these are expensive, but are a lot cheaper in the long run and the payments on one are pretty low. I pay about $26 a month plus salt that costs less than $10 for the same period for a properly adjusted softener. Don't even think about getting one from a hardware store or home center. These are garbage. Rent a Culligan, Besco or other professionally installed unit. You need one with a salt container separated from the conditioning tank. Again, the store bought units that have the tank inside of the salt container are garbage.
If you are using a detergent with bleach and silica (sand), it will not clean your dishes. This is good for bleaching out stains, but that's about it. Get an enzymatic detergent such as Cascade or Finish and stay away from store brands if they don't do the job. I use Finish Quantum and hand these out to my customers and this does a good job in my cheapie dishwasher. Phosphorus was a common ingredient in dishwasher detergents until a few years ago. Because this is impossible to remove through water treatment methods and creates a huge problem with algae, the Feds banned this chemical a few years ago and customers have been unhappy since. Such is the price of ecology.
Use rinse aid. Yes I know this is an added expense, but it's less than $10 for a bottle that will last you up to a year. This is actually a drying agent and helps prevent the food particles from settling back on your dishes. I use the store brand stuff, but you can use the name brand if you want.
Clean your filter if you have one. Many new machines don't use a chopper in the interest of noise. These have a filter in the bottom of the tub that's not unlike a dryer filter. Check these out regularly, preferably after each wash. Not only do you want to clean it, but make sure this is in good condition to help prevent damage to the pump. Some of these are not cheap nor fun to install. It would also be a good idea to clean the sump once or twice a year or oftener if you use it a lot. Sometimes access is limited as on my Amana, but most are pretty easy to get apart. Use a wet dry vac to get the water out and make sure this is no glass before sticking your patties in. Most of the time, this not a huge issue anyway.
In short, try these before calling the service provider who is going to have to tell you these things anyway. IF you do have to call someone, call a locally owned and locally managed one who has a stake in your community and follow their advice. Most of the time, these tips should help you out and save you the price of a service call. Saving money is what we're about these days. Maranatha!