How to Reset a Suitcase Lock Without a Reset Button

Method 1: systematic trial

Turn each dial slowly and feel for a "click" when the number is right. Repeat for each dial.

Method 2: a flashlight

Shine a light into the slot next to the dials. Turn until the inner notch is aligned. This works on most 3-digit locks.

If it doesn't work

Contact the manufacturer of the suitcase. As a last resort, a professional locksmith. And for the future: write the code down somewhere safe.