You will need to remove a light fixture from a mirror if the light has stopped working or is badly outdated. Follow the suggestions below to remove a light fixture from a mirror.
Step 1 - Determine How the Light Fixture is Attached and Operated
If the light fixture is wired into the wall, start by turning off the electricity to the switch and the room as a whole. Ask for assistance if you feel unsure about disconnecting the electrical supply to the light fixture. Pull back any window covers to let in natural light, or use a flashlight for the removal process. Climb up on the stepladder and examine the light fixture to see if it is screwed into the wall, attached to the wall with adhesive, or attached to the mirror itself.
Step 2 - Detach the Light Fixture
If the light fixture is screwed into the wall, it should have a flat round cover over the electrical components in the base. Push the putty knife carefully under the edge of this cover to release it. You will probably turn it counter-clockwise to detach it from the base.
Step 3 - Remove the Switch Cover and Disconnect the Wiring
You will see 3 colored wires inside the switch cover. They are most likely white and black, or white and brown, plus a green one. Disconnect these by twisting loose the wire connections at the switch, and gently pulling them up through the light fixture base on the wall.
Step 4 - Remove the Light Fixture Base
Use a wrench the correct size to loosen any nuts and bolts, or a screwdriver to unscrew the base. Once you have removed the light fixture and all wires, you can restore the electricity to the room. Reattach the light switch plate cover before turning the power back on.
Step 5 - If the Light Is Glued to the Wall
Loosen the adhesive on the light fixture with the putty knife. If the light is still stuck fast to the wall or the mirror, heat it up with the highest setting of a blow dryer. Hold on to the light fixture base while doing so, to prevent it from falling if it suddenly releases from the wall. If heating the adhesive is ineffective, apply a generous bead of adhesive remover around the light base and force it under the edge with the putty knife. Wiggle it gently to dislodge the base.
Step 6 - If the Light Is Glued to the Mirror
If the mirror is only attached to the wall by corner brackets, remove the mirror from the wall before trying to remove the light fixture, so it does not get broken or chipped. If the mirror is mounted with mirror mastic, loosen the adhesive holding the light fixture as described above, using both heat and the adhesive remover as needed.
When installing the new light fixture, you can use the existing light switch box or have the switch redirected outside the bathroom by an electrician.