Indiglo is a backlighting feature available on wide variety of Timex watches. The light illuminates the dial when you press a button, allowing you to see the dial in the dark. The light works by passing current along electrodes, causing a dial coated with a copper and zinc compound to illuminate. An Indiglo's original battery can last for years, depending on how much you use the light.
Locate the numbers on the back of the watch that are followed by the word "cell," indicating the type of power cell the particular model requires. Use the numbers to obtain a replacement battery.
Lay the watch, face down, on the cloth.
Remove the back of the watch with the proper size screwdriver. On some Indiglo's there will be four Phillips-head screws visible at the corners. If there are no screws look for a slot along the edge of the watch between the back and the body. Gently insert a flathead screwdriver in the slot and twist to loosen the back.
Loosen the battery bracket with the Phillips screwdriver and swivel it away from the battery.
Remove the old battery by turning the watch over. Insert the new battery, with the numbers up, and pivot the battery bracket back into place. Tighten the retention screw. Turn the watch over to see that the watch is working. Replace the cover.
You can buy the appropriate replacement battery for your Indiglo watch at most department and chemists.