August 14, 2025 
I checked the grill and round fan elementz and have low insulation resistance.
Furthermore when you switch the oven on the timer relay makes a buzzing sound.
After replacing both elements the grill is not coming on.
It does occasionally!
Checked function switch with multimeter and looks good.
Checked thermostatic switches and are ok too!
I do need the schematics of this oven zo that to do fault finding!
Can you supply me a copy of this model?Magri
Hi Magri, sorry to hear about your problem with Siemens HB331E1J/04 Oven,
If an element or multiple elements are causing an earth leakage greater than the consumer unit can handle, it will trip and cut off the electricity.
I can’t rely on the measurements you’re giving me because I don’t know the meter or any other details. I always suggest to customers that if they isolate those elements and the oven stops tripping, then that’s likely why it was tripping when they were connected.
You also mentioned you’ve disconnected the elements but remember there are 3: one in the top oven which is the grill element, one in the bottom oven which is the base element, and the other one is fan oven element. To isolate the problem, you should also disconnect the base element completely and take photos of where the wires come from. Once all elements are disconnected, reconnect the cooker to the power supply. If it still trips, then you’ve ruled out all the elements.
Make sure no wires remain connected to any element. Also, check the selector switch for damage as they can sometimes short to earth. Although it’s unlikely, you should also isolate and test the fan motors.
Lastly, check the connection block at the back of the cooker. You’ll need to go through these steps one by one to find which element is causing your electricity supply to trip.
When it comes to the wiring diagram and schematics, I am sorry but I can’t provide technical information on this oven as the manufacturer doesn’t release workshop manuals or wiring diagrams to us or the public. However, I was able to provide you the exploded view of your machine and the instruction manual which you can find them below. I hope this helps. If you need further assistance, feel free to contact us. I have also added some videos below that are worth watching
If you need a spare part for your oven, you can also visit our shop page.
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Paul Charmbury
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Video to help you with your Siemens HB331E1J/04 Oven
Siemens HB331E1J/04 Oven Exploded View of Parts
Siemens HB331E1J/04 Oven Instruction Manual