Casio's sporty and fashionable line of G-Shock watches can be spotted on celebrity tastemakers, such as Lady Gaga and Fergie. To satisfy G-Shock fans and collectors, Casio regularly collaborates with guest designers and to turn out new color combinations and bold styles each year. Despite the variety of G-Shock watches, the line uses similar, if not the exact same, part and features in all models. Fixing the lights on each of the timepieces requires the same procedure no matter which style of G-Shock you have.

Check the watch batteries. You'll know that the batteries need to be changed when the clock display begins to dim.

Unscrew the hatch on the back of the watch face, which serves as a cover for the battery compartment. Remove the cover and exchange the old batteries for new ones.

Press the "Reset" button on the watch to reset the clock after changing the batteries. The "Reset" button is inside the battery compartment and must be pressed before replacing the compartment cover.

Replace the cover of the battery compartment and press the "Light/Snooze" button to activate the light.

Navigate to the Authorized Service and Support-Service Centers on the Casio website to find the nearest repair center for problems with the G-Shock watch light that cannot be fixed by changing the battery.