Thank you for your post and welcome to the Bose Community.
I am sorry that you're experiencing a power issue with your QuietComfort 35 headphones. I would love to help.
When you say that they power on by themselves, is the Power switch in the off position? Or are the headphones on and are connecting to a Bluetooth source automatically?
If the switch is in the OFF position:
I would recommend resetting the headphones by following these steps:
1. Turn off the headphones and wait 30 seconds
2. Plug the headphones into a wall outlet using a USB charger, then wait 5 seconds
3. Unplug the USB cord from the headphones and wait 1 minute
4. Turn on the headphones
Additionally, please visit btu.bose.com on your computer and ensure that the latest firmware version is installed.
If the latter scenario, please let me know.
Charlotte G - Community Support
Thanks for your reply.
They come on when the power switch is off.
I have tried your fix to reset them, but still no luck.
These headphones are only 2 years old and I paid $350 to get Bose quality.
Thank you for trying that and letting us know, I'm sorry to hear it has not worked for you this time.
At this point, I would recommend getting in touch with your local support team, as they will be able to help you resolve this issue. You can find the contact information at this link, by selecting your country/region and then the 'Contact Us' option at the bottom of the page.
Let me know how you get on.