Our venerable Bosch dishwasher was showing signs of its age (13 years old). It wasn’t drying completely and the drying wasn’t consistent, sometimes okay, sometimes not at all.
Finally, today, a couple weeks after the drying started acting up, it stopped working at all. No light, no sound, no nothing.
After searching this site and finding some very useful information (wiring diagrams in particular) I spent about four hours working it through and ended up fixing it. I wanted to post it here in case it would be of help to anyone else.
The problem was that the main hot wire in the wiring harness broke down at the point where it bends when the door is opened and closed. Thirteen years x 365 days a year x say three times a day being opened and closed comes up to about 15,000 flexes for this conductor. So I suppose it was about time.
Troubleshooting was complicated by the fact that the connection to the neon bulb indicating power on/off was intermittent. After a lot of poking around I discovered that the solder connection between the neon bulb and the resistor that limits its current had broken, although sometimes the wires touched enough for it to work. Once I resoldered that connection it became a key diagnostic tool, as it indicated when power was present and absent.
A bit of door opening/closing and wire wiggling later I was able to get the power to come on and off by pressing on the right spot of the vinyl-reinforced wiring cover that protects the wiring harness as it exits the bottom of the door and threads into the base of the dishwasher. A little bit of utility knifing later I could see where the main hot wire had broken through the vinyl cover (perhaps because it had developed a hot-spot there), and that most of the strands of the wire had receded from the hot spot and that one or two strands would make intermittent connection depending on the position of the door and how I wiggled the wiring harness. The neon power light was a reliable indicator for when it was connecting.
I did some careful stripping and wire-brushing of the somewhat corroded wire, and then crimped on an inline connector. Voila, back in full action.
My theory is that the wire broke down strand-by-strand, and that as it deteriorated, it would not carry enough current to fully drive the heating element for drying. Of course as a reduced number of strands carried the drying current, those strands would become quite hot until the continuity broke down altogether.
Anyway, all is well now, just hoping this helps someone else.
I’m thinking 13 years is plenty to get out of a dishwasher, but my wife wants to put the money toward new carpets in a few rooms of the house, so I’m hoping this will hold it for another year or two.
