If it’s running and going to a dead stop, the main body could at fault. This houses the electrics. Pulsing is another story, usually meaning a blockage. Check out this link as a starter: 

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Power wise, there’s only three parts that can really be replaced. The battery, charger or trigger component. If the battery is charging, then the issue lies with the main body. 

Hello @Jannerl 

Thanks for posting a question to the wider community. 

Usually when your Dyson only runs for a few seconds, it may be 2 issues:

Either the filter is blocked, there is a blockage in the machine or the filter has become faulty and needs replacing. As mentioned you have done so already.

The second issue might be power related and you have mentioned that you have replaced your battery and filter already. So, in this regard you would need to look into replacing your main component which is the main body.

You can visit our website over here and place an order or you can simply get in touch with one of our Representatives over our WhatsApp platform to discuss the next steps. To do this, simply click on our Guides and manuals link, navigate to the ‘Contact us’ section of the page and start a WhatsApp conversation. 

If you still need any further help regarding this, don't hesitate to respond over here.

Regards,