My Bosch SHE56C05US dishwasher has run perfectly for 7 years, then last night in the middle of the first rinse cycle, when the washer was full of water, it started making a clunking noise. The front panel lights flick on/off, in sync to a click noise from a relay or breaker on the circuit board and a clunk from the base of the washer. It looks like power is being cycled on/off continuously.

It does not respond to the front panel service program, or any other buttons. I checked the drain impeller and it turns freely.

I measured motor resistance the and the main motor is in spec (7.7 ohms & 9 ohms), but the drain motor reads high at 25 ohms. Spec is 15-18 ohms.

Does anyone have any suggestions on what the problem could be?

Thanks for the tip about the control board.

There were two burned connections on the board, just as you suggested. I bridged them with wire and resoldered the connection, and all is well now. Took about 1/2 hour.

I'm surprised that Bosch hasn't yet learned how to design a reliable printed circuit board by now.