Bosch WAT28401UC/01 will not start cycle. Door latch opens and closes continuously

Washer Repair
1

Brand: bosch
Model Number: wat28401uc/01
Main Symptom: door latch opens and closes randomly
What happens & when: the washer beeps and you can hear the door latch opening and closing. It happens sometimes when you start the washer but also mid cycle

Error Code (if any):
Parts or tests already tried: I changed the door latch but this did not solve the issue
Photos / video link:

2

For Bosch WAT28401UC/01, since the door latch has already been replaced and the washer is actually cycling the lock/unlock mechanism by itself, I would not replace the latch again. Bosch confirms this exact E-number and provides model-specific service support.

Most likely causes

  1. Door-lock wiring/harness — check this first

    • Inspect the connector directly at the new latch.
    • Follow the harness back toward the control.
    • Look for loose terminals, backed-out pins, corrosion, or a wire broken internally.
    • Wiggle-test the harness while the washer is running.

    An intermittent lock-feedback connection can make the control think the door changed state, causing the beeping and repeated lock commands.

  2. Main control board — strong suspect

    If the harness and connections are solid, I’d suspect the control electronics that drive/read the door lock. The fact that it can happen mid-cycle, without anyone touching the door, is particularly important. The control shouldn’t normally be commanding repeated unlock/lock operation during an active wash.

  3. Check the door strike/alignment

    Make sure the strike enters the new latch squarely and the door isn’t sagging. Push inward on the door while starting a cycle. If the problem immediately changes, investigate hinges/strike alignment before condemning the board. Bosch’s troubleshooting information also specifically calls for checking the latch/lock mechanism when dealing with door-lock problems.

What I would do next

Don’t order another latch yet. Disconnect power, then check the latch-to-control harness end-to-end, including continuity while flexing/wiggling each section. Also inspect both connectors carefully for terminals that aren’t gripping the pins tightly.

If the wiring passes and the door/strike is mechanically good, the main control board becomes my #1 suspect.

One useful clue: when it acts up mid-cycle, watch the display. If the display flickers/reboots or other relays cycle at the same time, I’d investigate the control’s power supply/input. If only the door lock repeatedly clicks while everything else remains normal, I’d concentrate on the door-lock circuit/harness and main control.

3

Hi Jeffrey,

Thank you for the prompt response. The screen does flicker when this issue occurs. I wanted to purchase the control board but this washer has 3 different boards and I did not know which one controls the door latch.

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I’m glad I was able to help. Let me know if you need anything else

5

Sorry, forgot to ask you if you can point me towards the correct part I need to purchase since this washer has 3 separate boards. Is it the Inverter Control Board or the Power Module?

6

You need this one (Bosch 11003952 Washer Operating Module Not Pro | Genuine OEM Part) but it is no longer avaialable