I was having the same problem with my Bosch SHU43C05/43. It would run forever with 1 left on the timer. Inside was not particularly hot when opened at the end of the cycle. Some remaining water in the bottom of the dishwasher.
After searching the internet, finding this and a few other boards describing the problem, I checked the impeller blade and ensured no blockage in the drain hose, ran the diagnostic program (result:heater issue).
I saw MrMark52's post above. It appealed to me to replace the relay with a better one, rather than soldering the old one or a new board with the under-rated relay.
I was able to get the old board out myself and had MrMark52 replace the relay. I got it back promptly and reinstalled it without a hitch. The result: dishwasher is working great and I saved some money over a new board. Hopefully, this will outlast a new board with the under-rated relay. Thanks, MrMark52.