When only one of the Bose QuietComfort Ultra Earbuds plays, or one is much quieter than the other, the cause is typically a battery or charging difference, a blocked nozzle, a seating problem in the case or a connection fault between the two buds, and it can usually be fixed without a repair. The earbuds link to each other as well as to your phone, so one that has lost the link behaves as if it is dead. Put both earbuds in the charging case, close the lid and leave them for a few minutes, then remove them and listen.
The checks in more detail
A single earbud that has not charged because it was not seated, perhaps because of lint on its contacts, will be flat while the other is full; wipe the contacts in the case and on the buds with a dry cloth and re-seat them. Check the physical details. A nozzle blocked with earwax makes one side faint, so clean it gently with a soft dry brush and not a pin. Check that the tip is on firmly and the mesh is not clogged.
Check the balance setting in the phone, since a left or right balance slider in the accessibility menu can make one side quiet; reset it to the middle. In the Bose Music app, check that both earbuds show a battery level and a connection; if one shows disconnected, take it out of the case and see if it joins. If the problem persists, reset the pairing. Put both earbuds in the case, forget them in the phone's Bluetooth list and pair again by holding the button on the case.
A factory reset, described in Bose's help pages for the model, clears the link between the buds and often cures a stubborn one-sided fault, but it removes all pairings. Update the firmware in the app. Test the earbuds with another device, which shows whether the fault is with the buds or the phone. If one earbud is silent on every device after a reset and a clean, it may have a failed driver or a battery fault, which Bose will repair or replace under warranty with the serial number.
Differential
Likely causes of “Bose QuietComfort Ultra Earbuds plays from only one side or channel”, and how to tell them apart
- 1
One bud uncharged or not seated
What separates it One side is silent
How to confirm Clean the contacts and charge both in the case
- 2
A blocked nozzle
What separates it One side is faint
How to confirm Clean it with a soft dry brush
- 3
A balance setting
What separates it One side is quieter
How to confirm Reset the balance to the middle
- 4
A lost link between the buds
What separates it One bud shows disconnected
How to confirm Reset the pairing
- 5
A failed driver or battery
What separates it Silent on every device
How to confirm Contact Bose
Before you touch a setting
Record this first — changing settings destroys the evidence
- Which side fails
- The battery levels
- The balance setting
- Whether it fails on another device
Try in this order
0 of 6 completedCharge both in the case
ReversibleAnd clean the contacts.
Clean the nozzles
ReversibleGently.
Check the balance
ReversibleIn accessibility settings.
Pair again
ReversibleAfter forgetting the earbuds.
Reset the earbuds
ReversiblePer Bose's help.
Contact Bose
ReversibleIf one stays silent.
Model-specific
What is true of this model and not of its siblings
- Linked buds
- They connect to each other.
- Contacts
- Lint stops charging.
Stop boundary
When this stops being a self-service repair
- !If one earbud is silent on every device after a reset, contact Bose with the serial number
- !Update the firmware first
- !Clean the contacts before concluding it is faulty
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why does only one earbud work?+
A flat bud, a blocked nozzle or a lost link.
How do I check the balance?+
In the phone's accessibility settings.
Will a reset help?+
It often fixes a lost link.
Is it covered by warranty?+
A failed driver is.