Unfortunately, watch batteries do not last forever. When it comes time to change the battery on the Timex Indiglo watch, it is fairly easy to do as most models are designed and function the same way. Each Timex Indiglo watch is a different style, but the essential part and construction are the same between model numbers.
Unlatch the clasp on the wristwatch; lay the watch with the clock face downward. You can lay it on top of a soft surface, such as a towel, to avoid damaging the watch face.
Remove the back panel of the watch. Depending on the model, this will be done with either a small Philips screwdriver or by using a flat head screwdriver to pry off the back. Pry it open where you find a slotted area along the edge of the watch's back plate.
Remove the screw that holds the battery bracket inside the watch. Twist the bracket to release the battery compartment.
Flip over the watch and tap the face to allow the old battery to drop out. Place the watch back down on its face. Place the new battery in the old battery's compartment.
Swivel the battery bracket over the new battery and replace the screw.
Ensure that the battery is functioning properly before replacing the back plate of the watch.