Pool lighting comes in many styles and types.
Digital Vision./Digital Vision/Getty ImagesPool lights provide a colorful, decorative touch for your swimming pool while also illuminating the water and making it safer for nighttime use. Some pool lights shift colors for a continually changing look. If your lights come on but don't change colors when they should, you can isolate the problem before undertaking repairs.
Motors
Some pool lights that change colors rely on small motors that rotate a multicolored lens so different portions of the lens filter the light being emitted by a single bulb. These lights are susceptible to motor failure, which will allows them to function normally but without any color change. Depending on the position of the lens when the motor fails, the light will remain a solid color whenever it's turned on.
Bulbs
Other pool lights with multicolor features rely on several different colored bulbs. This type of light can fail when one or more colored bulbs burn out, which all light bulbs do, eventually. A faulty light may display one color, then go dark when it would normally display another color. With this type of problem, replacing the affected bulb is the only solution.
Wiring
Wiring can also cause a multicolored pool light to experience problems. While a problem with the electrical supply will cause the entire light to stop illuminating, a problem with the wiring in the light's housing can cause the motor, or an isolated bulb, to stop working properly. Wiring problems, like motor problems on motorized color-changing pool lights, can't be repaired with a simple bulb replacement.
Repair Options
The repair options for a pool light that comes on but doesn't change colors depend on the source of the problem. In most cases, you'll need to remove and repair the light itself, since the fact that the light illuminates indicates that problem doesn't involve your electrical system or wiring. Most pool lights screw into place and have waterproof housings, which means that once the power is turned off you can remove them by hand. Dry off the housing and open it to reveal and replace dead bulbs, a faulty motor or damaged wiring.