Bosch Dishwasher Cycle issues

[the_baldguy]

Hi -

Rookie here, relatively handy, have taken many things apart.  Often they go back together and sometimes they even work.

I have a ~1yr old Bosch SHX68T55UC/07 that is pretty wonky.

Behavior includes:

• Stopping mid cycle (power off)
  • Pressing power may or may not work when it turns off.  Position of the door may allow power button to work, but often it shuts off as you swing the door closed.
  • Most often when power is pushed to light it back up, the time on the display is ~1hr left on an AUTO cycle (2:04 on display at start) but it has stopped relatively early in the cycle also.
  • maybe 80% of the time it is restarted it will run to completion.  The rest require Power button + Start button to resume the cycle
  • Sometimes when I am awake and close enough to hear it running through a cycle it will turn on and off repeatedly. (we run it overnight)  If I open the door at this time it is full and hot (steam escapes door).  Same door position behavior, opening door may cause it to lose power, closing slightly may light it back up. Location of door is random - it doesnt turn off at the same door position each time
• Often in the morning it will be "off" rather than showing "clean".  It rarely seems to finish at "clean" but since we dont run it in the day that could be caused by it turning itself off after it gets to "clean" and us just not being around to see it at "clean"
• It will randomly turn itself "on".  (beep + display on top of door is alive)  It will not start a cycle, but will beep on, then turn off,  then beep on... and do that randomly back and forth as long as it wants.
  • I can sometimes get this on and off to stop by opening the door and manually pushing POWER to turn it off.  But just as often it will go back to beep on, off, beep on, etc.

I am guessing there is water getting into a board or connection, or a board or connection is lose and the heat from the cycle causes it to 'open' (although this doesnt really explain the random turning on for me, but again I coming from relative ignorance here)

I am hoping there is a way to somewhat definitively figure out what is up or at least get some steps of things to check and test.

I like to tinker and have the tools, but if you deem this above my pay grade then if there is a reputable repair co in Boston Metrowest (Natick) I am open to that.

Just not keen on the dart throw that calling Bosch support seems to be.

(I think they referred us to sears repair with a $125 min to show up, and if that test run is the one in ten that cycles to completion without issue (as Murphy would have it) then I am sitting with a bill and a still wonky dishwasher)

I have film of most of the behavior (although that may be dating myself, let's call it Video)

I have seen posts in random forums stating that the door latch is an issue, and from what I can tell this is not the cause here.  I can have the door open and it will still turn itself on and off.  So I dont think it is the door popping open during the cycle.

Additionally, if it matters, we use Cascade Gel and Cascade Rinse Aid. (against what the sticker says, but in the Bosch at my old place we got the cottage cheese in the filter and associated stink when using Finish)

Thanks

 

[Rhubarb Tau]

If it were me, I think I'd zero in on the intermittent poweron / poweroff behavior that seems related to door position. If you're comfortable working on the unit while powered up (safely, carefully, double-insulated, etc...), I would try pulling the outer door skin, carefully jiggling the wiring up to the console along its length, and watching closely to see if any areas of the wiring seem to cause glitchy poweroff / poweron.

If you find a stretch of wire that seems to reliably cause glitchyness when prodded, drill down to see if there's a single wire in the bundle that reliably causes glitching, then ohm it out with the power off to find the exactt spot that needs attention / rework.

[MoTeD]

Definitely sounds like a wire harness issue. 

[the_baldguy]

Thank you for the responses - here is what I have for follow up.

I was working from the island next to it today and it was closed completely (clicked) and constantly beeping on and off.

I opened the door, pushed the power button to turn it off, and closed the door.

Within 5 minutes it was turning itself on and off again.

There were dishes in it when it was doing this (I had run it this morning) so I emptied everything and pulled the panel off.

All the wires look intact. Everywhere there is a connector it looks connected and dry.

I closed the door (panel still off) and ran an 'express' cycle (<1hr, no dishes, no soap).  That ran to completion (clean notification) without issue.

I ran an 'Auto' cycle (2:04, no dishes, no soap).  That ran to completion (clean notification) without issue.

I loaded up the breakfast dishes and ran 'Auto' again with soap.  That ran to completion (clean notification) without issue.

I cannot recall the last time I got a 'clean' on the display after any cycle on this machine (maybe 9 mos ago) so tentative deduction is that panel off resolves the issue, although from initial investigation I am not thinking that the panel itself is the cause.  No loose/bare wire, no pinching, etc.

My thinking now is a faulty latch sensor.  Is that magnetic or pressure sensitive?  (it is the pop/snap kind - pops when the door closes, pops when you open the door, no button)

Perhaps it thinks that the door is opening when the cycle is going?  I think I do recall seeing the panel light up when the door was closed, Ill have to go through and see if I can find if I took a video of that.

I might have time to take that off and examine it today.  The wires coming from the panel travel up and around the soap res (protected) and then behind the plastic to the latch so I dont think that the door panel would have impinged or otherwise affected the wires.  Maybe there is gapping or something with the door on that is letting moisture/steam get in there and affect the functionality when the panel is on (although it looks pretty much the same as I attach the panel)

I didnt see anything that the panel would directly cause, no pinched wires, no bare wires, so I think that the fact that it worked with the panel off was secondary. (if it is a moisture/latch issue, maybe the lack of panel let it breathe better so it didnt get wet enough to fail)

Any thoughts would be appreciated.  And I am assuming a latch sensor divot thing is something I can purchase?

Best -

 

[the_baldguy]

A few things to update, would appreciate some help to locate appropriate diagrams and parts.

I took everything apart and ran a few cycles with the control panel detached from the framework but connected to the wiring. (so the white plastic box containing the board and buttons removed from the black plastic frame that attaches to the door and everything detached from the door)

It turns out that somehow the buttons can self register presses with pressure on the sides of the containing white plastic box.

I can put gloves on and squeeze/torque the white box containing the circuit board/control buttons and it will register random button presses up and down the length of the buttons.

So, I think something is faulty in the board or the foam pads that transfer the pressure/touch to the board contacts.

I think that the pressure from the screws holding it all together is just enough to make all of the contacts almost closed, and then when the machine heats up during a cycle it will eventually close the connection to the power button and turn the machine off mid cycle.

So I am not sure if I replace the whole box (plastic container) or just the board, and if I should also replace the harness.

I would also like any links to schematics and or diagrams so that I can make sure I put things back together in the correct order and connections.

Thanks in advance -

[darren412]

I would check the dishwasher's power cord terminal block that is located in the white  electrical box that comes with the power cord for the dishwasher.  Bosch has had problems with these power cord boxes and intermittently shutting the power off to the dishwasher because of a bad connection with its terminal block.  I would check that for a bad connection in there somewhere or possible burnt terminals and connections in this box.