If this is a vinyl liner pool, chances are it's an Aqua Lamp system, which is the most popular brand although there are others such as Swim Quip. If it's an Aqua lamp, unplug or turn off the power source to the controller (transformer). Press your palm against the lens of the light and twist it counter clockwise half an inch. You'll hear a %26quot;click%26quot; as the two tabs holding the light assembly disengage from the light. Simply pull the housing up and out of the water. The cord should have been left long enough when it was last installed (it's wrapped up in the light niche) to allow you to sit the light housing on the deck, out of the water. Unscrew the four phillips head screws on the lens cover and set aside. The light bulb should come easily out of the housing and you'll only need to disconnect the two electrical wires from the back of the bulb to completely remove it. You'll also need to remove the large O ring you'll see there. There should be a new O ring supplied with the new bulb. Clean the interior of the housing to get rid of any algae or dirt, install the new O ring and hook the two wires back up to the new bulb. This is a 12 volt DC system, so as it's a light and not a motor, it doesn't matter which wire goes to what terminal. Place the bulb in the housing, making sure not to pinch the new O ring and that it seats correctly and evenly. Put the lens cover back on and hand tighten only, the four screws. Make sure that O ring doesn't pinch and that everything is sitting evenly! Installation of the new bulb in it's housing is the reverse of taking it out. Locate the two slots on the back of the light housing, stuff the light cord back into the niche ( that's the area in the pool wall that the light sits in) and line those slots up with the two posts on the niche. Press in gently and rotate clockwise half an inch. You should hear a click. Your're done. Power up the light.
If this is a concrete pool, their lighting is a little different in that it's not advisable for you to do the actual bulb swap. These are 110 volt systems with delicate seals on the bulb housing. Even mishandling the new bulb before installing it can cause expensive issues. If you are relatively handy, you CAN remove the light assembly for repair, but the actual repair itself should be done by a qualified person. Some of those bulbs cost 250 bucks. You mess up and you're out that money at the very least not to mention a possible shock hazzard. I'm going to describe how to get the housing out to take in for repair. I DON'T suggest that you attempt the actual repair yourself. All power, including the GFI circuit breaker at the panel, should be turned off. Most of these lights havce a single screw that hold them in the niche, located at the top of the lens housing. Unscrew it. Depending on the make and model, the light will either just drop out or require a slight counter clockwise twist. Like the Aqua lamp, there will be sufficient cord stuffed in there to allow you to bring the housing up onto the deck. That's it for the light for now. Just above the wall niche will be a circular deck box. The lid is usually fastened with four screws. Remove them and pry up the lid. If you find wax or what's called dux seal filling the interior of the deck box, you'll need to remove it to undo the wires in there. There will be two loads and a ground attached to the light cord. These are the only wires you need to undo. Leave the ground from the house alone, there's no need to remove it. When the wires are undone you have one more thing to do before you get the light out and that's to undo the compression nut in the deck box. It's the nut looking thing that the actual light wires come up through, from the bulb housing and it's threaded on the top of the light conduit. Counter clockwise until it's off. Store it and the washer in a safe place. The pool light will now come completely out. Just pull on the cord from the actual light end and all of it will emerge in the pool. Don't worry at this point about getting wires wet, it makes no difference as the actual cord the wires sit in is water proof, even at the open end. You now have your light out and can take it to a pool shop to have it replaced and tested. After they replace the bulb and seals they test it in a tank of water to make sure there's no stray current. That's why I don't suggest you try to do the entire repair. Installation of the new bulb in it's housing is the opposite of the removal. DO NOT forget to hook the ground wiring back up properly and replace any packing material that was in the deck box.
There is one other type of pool light, though not common and that's a fiber optic. If you have one of these, the bulb is located in the controller box. Remove the environmental cover and you'll see the halogen bulb right there, simply disconnect it from the power supply and match it up at the pool shop. Be careful handling the new bulb. Oil from a finger on the bulb surface can actually blow a new bulb.
As for draining the pool. Totally not needed. If the light was installed correctly in the first place, there is enough cord to get the assembly up on the deck where you can work on it in air. You're cutting all power, so that's not an issue either.How to change a swimming pool light?you will have to drain the pool just below the light turn off the electicity and then change the bulb turn the electricity back on then fill up the pool. i thinkHow to change a swimming pool light?I assume you mean the light in the pool itself. You should turn off the electricity first of course and then just remove the old bulb and replace it with a new one. All the components in the light setting are waterproof.
