13 replies to this topic

[Tim M]

Of course it's behaved for the last 3 washes before I got here. Before that the timer would stop at 6:00 and it would continue to run for hours.

Input water was only 104°F, but when I was here it drew 11Amps and heated up no problem. It's a hand crank timer, so I don't know if there is a solder joint in a circuit board to look at.

Intermittent problems are hard to diagnose, so I could use some help.

Thanks.

[Tim M]

Hmmm. Bosch dishwasher service manual doesn't seem to have a wiring diagram for this one.

[RegUS_PatOff]

Hmmm. Bosch dishwasher service manual doesn't seem to have a wiring diagram for this one.

SHU 40
pages 111, 112, 113
(PDF pages 113, 114, 115)

[Tim M]

The temp sensor on top of the dispenser was loose. When I disconnected that I got it to hang up, but that doesn't mean that was the original problem.

Reg_US, was that supposed to be a clickable link?

[Samurai Appliance Repair Man]

Hmmm. Bosch dishwasher service manual doesn't seem to have a wiring diagram for this one.

SHU 40
pages 111, 112, 113
(PDF pages 113, 114, 115)

The temp sensor on top of the dispenser was loose. When I disconnected that I got it to hang up, but that doesn't mean that was the original problem.

Reg_US, was that supposed to be a clickable link?

No, he referencing the pages in the manual that you indicated you already have.

[Tim M]

If that's the 119 page Bosch Dishwasher Service Manual or the 144 page Training Manual, it doesn't seem to be the one for a 4002. The complete guide had something similar, but still some wire colors were incorrect.

Anyway, it doesn't matter if I can't get it to reproduce the problem.


Could a low household water temperature of 104°F be bad enough to make it hang indefinitely? Couldn't it heat even cold water up to temp eventually, making it run for an extra hour, but not an extra 12, like it reportedly has been doing?

[RegUS_PatOff]

that would be ... of the 144 page manual
OK try these:

Bosch dw SH1 Repair.pdf 5 MB
bosch_shu.pdf 10 MB
bosch-wiring-diagrams.pdf 11 MB
links PM'd

[Tim M]

Cleaned the gunk off the sensor over the dispenser. Mucked around a good deal, but nothing definitive. I hadn't charged, since I wasn't sure I'd fixed anything. After weeks of performing correctly, I accepted payment on the homeowner's insistence.

[Tim M]

Drat!

Now I've got two of these doing this. Both are intermittent problems, so it's hard to test. On both the timers hang up in the wash cycle and won't let it finish. Likely heater circuit. There's no control board, it has a timer:



So I'm sure that it isn't the usual unsoldered heater relay.


So if I can't get it to do it while I am there, what can I do? Replace something and hope for the best?

Now it could be the selector switch


but there is nothing visually wrong with that.


On one of them I tested the regulator


but that seemed okay.


The only thing left is the PTC/Hi limit



that could be intermittent.

The element itself couldn't be intermittent, I don't think. Wiring harness could be, but not the most likely.


What have you seen go on these that I should be considering? With two Bosch dishwashers on good old-fashioned timers doing the same thing, I'm sure it's something that happens all the time.



Thanks for all your help.
Tim

[jumptrout]

The wiring harness goes underneath inside a black plastic sheath.
I had one of these recently with a similar problem.
A large white wire inside the sheath was nearly broken.
I cut the wire and put it back together with a buut splice.
It has worked fine since.
After opening the wire sheath I felt the wires and felt abnormal heat from the wires.
Touching and feeling resulted in a wire feeling bulged.
That was my bad wire.
Open the sheath on the front lower left where the wires go underneath and check each wire while running.
Feel for a deformed or warm wire.

[Tim M]

At least one of them has the newer, plastic hinge for the wires to run through. I opened it up and didn't find anything at that time, though so far it is the only thing I have to try on the next visit.

Tim

[wobiii]

You ever get this one figured out?

[Tim M]

You ever get this one figured out?

No, and I've looked all over the web, and no one else seems to have a clue either.  Found a few posts on it elsewhere, but none with any answers.

[Tim M]

Hmmm ladies and gents,

.   New ideas.  I was working on a washing machine recently with a sticky timer/welded contact, that I might have misdiagnosed as something else were it not for the help of these forums.  This morning I was doing my own laundry, and my Staber, which I love, hung up at the usual point where it very occasionally (read intermittent problem) does.  After ruling out the lid lock switch, I've surmised it is most likely the timer, but is so infrequent I haven't done anything about it yet.

 

.   While I was thinking about my Staber, I thought about the other washer, and was thinking about starting a general discussion in these forums on timers and why and how they misbehave.  Then these two Bosch Dishwashers came to mind.  I'm not sure they are both stopping at the same point, though they both have the same result of running too long.  I'm beginning to wonder if it could be the timer itself getting stuck at some point because of a welded contact or otherwise.

 

.    Given how infrequently they both do it, it would be hard to test.  If I replace the part, it would be quite some time before I knew if it was successful. Given that parts bought through this forum can be returned even after they have been installed installed, up to a year later, I'm beginning to wonder about trying it out.

Edited by Tim M, 17 February 2013 - 11:49 AM.