Frigidaire dishwasher model FGIP2486UF0A had been working great. Recently I've been noticing the dishes aren't getting dry even with the dry setting turned on. They are still coming out clean. Also, there is a greasy orange buildup on the interior surfaces of the dishwasher. I manually scrubbed down the inside of the dishwasher, as well as pulled out the screen and spray arm parts and washed them by hand to get the residue off. After a week or so the residue comes back.

Water temperature going into the DW is 120 degrees F. I tried using one of the dishwasher cleaning products that has a wax plug in it that melts open and releases the cleaner, but after a cycle on the highest heat setting the wax plug is still intact. I think the DW heating element is not heating up.

I checked the resistance on the heating element, its 14.5 ohms, so I think that is ok. Can I check/replace a thermo sensor or something?

thanks!