How to Replace a Bathroom Vanity Light

If you know how to replace a bathroom light fixture, you have an easy way to give the bathroom a basic makeover without having to do much renovation work. In particular, a new vanity light can make a dramatic difference to the space, especially if you clean up the bathroom mirror or install a brand-new one along with the new light fixture.

Since the wiring is already in place in the wall, this project is usually easy enough to DIY without calling an electrician. A bathroom vanity light fixture typically comes with a mounting plate that screws to the electrical box that's already in the wall, so all you have to do is disconnect and remove the old vanity light fixture and reverse the process to install the new one. This simple home improvement project is similar to replacing a ceiling light or installing wall sconces.

Here's a step-by-step tutorial on how to remove an old bathroom vanity light fixture and replace it with a new vanity light of any standard type.

Before doing any electrical work, it's important to turn off the power at the breaker box. Don't rely on the light switch because someone could inadvertently turn it on while you're working and give you a shock. Shocks are more dangerous in the bathroom because of the water there, so play it safe and locate the circuit breaker for the bathroom lighting, switch it off, and leave it off until you're finished working. Bathrooms often have two circuits — one for the lights and one for the outlets — so make sure you turn off the right one. If you aren't sure, turn them both off.

If the existing fixture has glass shades, they are usually held in place with small thumb screws. Loosen the screws to release the shades and be careful not to drop them when you remove them. Unscrew and remove the light bulbs. Set the shades and bulbs somewhere safe and out of the way.

Some electricians apply caulk around the perimeter of fixture mounting plates to protect wiring from bathroom moisture. If your fixture has been caulked, cut through the caulk with a sharp utility knife to prevent pulling paint off the drywall when you remove the mounting plate.

To begin removing the old fixture, loosen and remove the screws on the mounting plate, set the screws aside, and gently pull the fixture forward a few inches until you can access the fixture wiring. Be careful not to touch the wires.

You've turned off the circuit breaker, so the wires in the wall should be dead, but it's prudent to test them with a voltage tester just to make sure. Using a non-contact voltage tester, touch the tip of the tester to each of the wires connected to the fixture and to any additional wires in the box. The tester should detect no voltage in any wire. If the tester lights up and/or beeps during the test, return to the breaker box and shut off the correct breaker, then test the wires again to confirm the power is off.

Support the fixture on the top of the ladder (if necessary) while you reach behind the mounting plate and unscrew the wire nuts holding the fixture wires to the electrical wires in the wall. When you've removed the wire nuts, you should be able to pull the fixture away. If the ground wires are still twisted together, use a pair of pliers to untwist them.

If the circuit wires have at least 1/2 inch of exposed wire on the ends and the wires are relatively straight, you can leave them as they are. If insufficient wire is exposed, use wire strippers to remove more insulation. You can also use the strippers to straighten the wires if they are bent.

The mounting bracket for a light fixture is known as a crossbar, and the one that comes with your new bathroom vanity light fixture may be different from the one supplied with the existing fixture. If so, unscrew the old crossbar from the electrical box and screw on the new one. If the two crossbars are identical, it's OK to reuse the old one, but you may want to replace it anyway.

Unpack the fixture from the box if you haven't done that already and unfurl the wires. You'll see a white wire and a black wire, each with an exposed end, and you'll probably also see a bare ground wire. If the ground wire is missing, look for a green grounding screw on the side of the fixture's junction box. That's where you'll attach the circuit ground wire.

Support the fixture on the ladder while you make the wire connections. Twist the white fixture wire together with the white circuit wire in a clockwise direction using pliers, then screw a wire connector (wire nut) onto the exposed ends. The wire connectors should be supplied with the fixture. Splice the black fixture wire to the black circuit wire in the same way. There should be no bare wire showing outside the connectors; if there is, use larger connectors, or trim the wire ends (provided they are at least 1/2 inch long) and reinstall the connectors.

If the fixture has a bare or green insulated ground wire, twist it together with the circuit ground wire (the bare one) and screw on a wire connector. If the fixture has a ground screw, wrap the circuit ground wire around it clockwise and tighten down the screw with a screwdriver.

Using the hardware provided, mount the fixture onto the crossbar. Some fixtures come with machine screws that must first be secured to the crossbar with nuts. You then poke the screws through the holes in the fixture mounting plate and hand-tighten capped nuts to hold it. Other fixtures mount by aligning the holes on the mounting plate with those on the crossbar, inserting screws and tightening them with a screwdriver. In any case, follow the mounting instructions supplied with the new fixture.

Screw a light bulb into each of the fixture sockets. If the fixture comes with glass shades or covers, install these per the instructions. Some screw on, and some are held by thumbscrews. In some cases, the shades must be installed before you can screw in the light bulbs.

Turn the bathroom circuit breaker back on and flip on the bathroom light switch to make sure the lights come on.

Need to see the process visually? Check out this video from Big Al Repairs: