[OrvD]

This is a summary from an earlier thread. Our DW cycle hangs up on Power Scrub, Regular and Delicate (not Rinse) and requires advancing the dial about ¼ inch, once in “wash” and once in “rinse”, to complete the program. From comments on Bosch DW's this sounds like a DW htr system problem.

The resistance at the heater terminals is about the required 11 Ohms.

The NTC resistance did not measure the required 55 kOhms at room temperature. Although the water flow switch resistance, with contacts closed, was about 0.4 Ohms, I replaced both.

However, there was no change. The dial stuck at about 5 o'clock (wash) and 9 o'clock (rinse), and the DW did not heat the water.

I by-passed the Tstat (near dispenser) by joining the two wires together and ran a regular program. About 15 minutes after the dispenser opened, I checked the water temp. It had dropped about 3 degees C (from about 45C when the hot water was tested in a glass). The timer ran through the complete program, but the washing quality was about 80% of the original effectiveness.

I tested the Tstat by heating a glass of water to about 65 degrees C. The Tstat closed quickly and I did a series of tests as the water cooled. It tested open when the temperature reached about 57C.

As I have replaced the NTC and the flow switch, the heater element showed a resistance of about 11 ohms, and the Tstat tests positive… what can I do next?

Do I need to go back to the heater element test? Is it possible there is a contact open at the dial or somewhere else that is the culprit? Is there a wiring diagram that I should use to trace the connections?


Help!

OrvD

[Gene]

You've done everything possible with the heating parts.

The first failure suspect in the line is the selector switch. Choose the "regular" cycle and check for continuity across the terminals 1 & 2, 3 & 4 and 5 & 6. All circuits should be closed.

If anyone is open - replace the selector switch.

If there is nothing wrong - replace the timer.

- The part number for the selector switch is AP2804338

- The part number for the timer is AP2804275

Here are the break down diagrams and the wiring schematic for the Bosch dishwasher Model SHU4002 UC/06

Gene.

[OrvD]

It looks like the selector switch (results below). I got the same results at the selector switch contacts with the wire harness plug disconnected, and at the terminals of the selector wires where they attached to the timer and ground when the plug was reconnected). Contacts 5-6 were open in all cycles.

Might this just be corroded contacts or is it an unrepairable fault within the selector switch?

CYCLE CONTACTS 1-2 3-4 5-6
Regular closed closed open
Delicate open closed open
Rinse closed open open
Scrub closed open open

[Gene]

No doubt the selector switch caused the problem. It has to be replaced.

Gene.

[OrvD]

Gene... the selector switch has been rec'd and installed...AND the DW is back to normal. Thanks for seeing me through on this case.

Orv D

[Gene]

I'm glad you were able to fix it.

Gene.

[tmorin]

Hi Gene

I've been troubleshooting a similar Problem as OrvD. Timer gets stuck. I short the temp sensor on the front door and the cycle completes. We only use the Power Scrub cycle. I just replaced the temp sensor on the bottom near the heater too see if that was the culprit, I replaced the temp sensor on front and the cycle didn't complete. Heater ohms out to about 11 ohms.

I measure the following with the connector attached to the control board

sw 1-2 , 3-4, 5-6

Reg C , C, C
Del O, C, C
Rinse C, O, O
Scrub C, O, C

And with the connector disconnected :

sw 1-2 , 3-4, 5-6

Reg C , O, C
Del O, C, C
Rinse C, O, O
Scrub C, O, C

All are the same except for Reg cycle which we don't use. Is C, O, C correct for the power scrub cycle?

Tim

[Gene]

Hi Tim,

What is the complete model number of the dishwasher?

Gene.

[tmorin]

Shu 4006uc/u06

On another note. How long should a dishwasher last? Any preference for brands? Our #1 requirement is reliability and then low noise.

[Gene]

Hi Tim,

The push button switch is not good due to the testing results you posted: C, O, C for "regular" is wrong. It's hard to say what else could be wrong because of the age of the dishwasher and lack of technical documentation for such an old model.

I believe Bosch is a very good dishwasher. It is very silent and is designed very professionally.

Reliability today is not like it used to be 15-20 years ago on everything. If you decided to buy a new dishwasher, make sure you will get good manufacturer warranty and it could be a good idea to buy an extended warranty (if it's reasonably priced).

Here are the break down diagrams for the Bosch dishwasher Model SHU4006 UC/06

Gene.