The output FETS could be blown. You need to bust out an O-Scope to see if you are getting gate drive from the driver IC. These amps are like $80 used so you may have a hard time finding a tech to fix it for less than $100. Good luck!
johng, I had a similar issue with an an LG dishwasher. Mine turned out to be a little flap of rubber that is supposed to prevent the waste water from coming back into the bottom of the dishwasher. When I took the bottom of the dishwasher apart that little flapper was in two pieces. After replacing that my dishwasher drains as it is supposed to. Hope this helps.