How to Fix a Doorbell

Closeup of an electrician rewiring a doorbell

The Spruce / Kevin Norris

Project Overview
  • Working Time: 15 - 45 mins
  • Skill Level: Beginner
  • Estimated Cost: $10 to $20

One of the best things about fixing a doorbell is how simple it is. A wired doorbell only has five major parts. So if something isn't working, it's easy to track down the problem and fix the doorbell.

What Is a Wired Doorbell?

A wired (or hardwired) doorbell is powered by household 120V electricity lowered to a 16V operating current by a transformer. A thin wire starts at the doorbell button and runs to the transformer and chimes inside the house.

Before You Begin

First, understand the terminology and functions of a wired doorbell's five major components:

  • Doorbell button: Located outside next to the front door, the doorbell button is attached to the doorbell wire with two screws on terminals.
  • Doorbell wire: This thin, double-stranded wire runs from the back of the doorbell button, through the house, and connects to the doorbell transformer and base (chime) unit.
  • Doorbell transformer: Located inside the house and attached to a 120V electrical box, the doorbell transformer has two exposed terminals with attached wires. One wire leads in from the doorbell button. The second wire leads to the doorbell base or chime.
  • Electrical box: The electrical box is a metal box with a 120V cable leading in from the electric service panel (or, the circuit breakers).
  • Doorbell base or chime: The doorbell base or chime is the chime unit—the part that rings.

Safety Considerations

Before working on the electrical box, turn off the power by shutting off the circuit breaker on the electric service panel. The low-voltage wire on the back of the doorbell button carries 16 volts. But the inside of the electrical box is energized to 120 volts, a voltage level that can result in minor injuries or, in some cases, can be fatal.

What You'll Need

Equipment / Tools

  • Phillips or flathead screwdriver
  • 110-220V AC/DC voltage tester
  • Electrical tape


  • Doorbell button (optional)
  • 20- or 18-gauge bell wire (optional)
  • Doorbell transformer (optional)
  • Wire nuts


Tools needed to troubleshoot a doorbell

The Spruce / Kevin Norris

  1. Check Doorbell Button

    If the doorbell button isn't working properly, it cannot complete the electrical circuit and cause the bell to ring. A simple way to test if the button is mechanically working is to temporarily bypass it by removing it.

    1. Use a manual Phillips or flathead screwdriver to turn out the screws holding the doorbell housing to the house exterior.
    2. Pull the doorbell and the wire out a few inches.
    3. Disconnect the two wires from the doorbell button by turning the screws counter-clockwise.
    4. Fold a large piece of electrical tape over the wire to prevent it from falling back into the wall once the button is detached.
    5. Touch the bare ends of the two wires to each other. If the chimes ring, the doorbell button is faulty and should be replaced.
    6. If the chimes do not ring, reattach the doorbell wire but do not attach the button to the house.
    Pulling doorbell wires out of a drill hole in siding to examine them

    The Spruce / Kevin Norris

  2. Check Doorbell Wire

    The thin, 20- or 18-gauge bell wire leading away from the doorbell button may have become damaged or severed between the button and the wire's two end-points inside the house: the transformer and the doorbell base (chimes).

    1. With the doorbell button still detached from the house, grasp the wire and gently pull the button as far from the house as you can. Apply light pressure only. If the wire is detached nearby within the wall, the entire wire will easily slide out, indicating that it has been severed.
    2. Locate the transformer. The doorbell wires should be firmly attached to the terminals. They should be curled clockwise under the terminal screws. If they are loose, remove and reattach them.
    3. Often, the final few feet of doorbell wire will be exposed as it leads up to the terminal. Check the exposed wire for breaks or nicks. Replace damaged wire by splicing in a doorbell wire of the same gauge.


    The doorbell transformer will be located indoors. It may be in the garage, utility room, pantry, hallway, closet, under stairs, crawl space, or in the attic. It will be a silver or gold colored box about 2-1/2 inches square. (Note: some homes will have a 2-3 gang electrical box behind the doorbell chime which houses the transformer.)

    Checking the existing doorbell wires for functionality

    The Spruce / Kevin Norris

  3. Check Doorbell Transformer

    Being a solid-state device, the transformer itself rarely will fail. But its connections may have failed or it may have become damaged or dislodged from the electrical box.

    1. Use the low-voltage tester to test whether the transformer is receiving and transmitting power. Touch the two test leads to the two terminals on the transformer. The tester should signal that the unit has power.
    2. If the unit has no power, check the electric service panel to make sure that the circuit breaker is flipped on.
    3. If there is still no power, turn off the power at the circuit breaker and install a new doorbell transformer.


    Test only the terminals on the outside of the transformer. Do not open the electrical box and test inside.

    Checking the doorbell transformer for an electrical current

    The Spruce / Kevin Norris

  4. Check Doorbell Base

    1. Remove the doorbell base cover.
    2. Touch the leads of the low-voltage tester to the two or three terminals on the doorbell base as an assistant pushes the doorbell button. If the tester indicates power, then the chimes might be stuck or need cleaning.
    3. Tap the chimes with your finger to loosen them if they are stuck.
    4. If the chimes are dirty or have cobwebs or other debris, they should be cleaned. Turn off the power to the doorbell system at the service panel. Carefully vacuum the chimes with a soft brush attachment.
    5. If the chimes need more cleaning, wipe them off with a cotton or microfiber cloth and isopropyl alcohol.
    Checking the doorbell base

    The Spruce / Kevin Norris

When to Call a Professional

Unless you are experienced at electrical repairs, you may want to call a qualified, licensed electrician if:

  • The transformer needs replacing
  • The doorbell wire within the walls or ceiling is severed and a new wire needs to be fished through
  • The 120V electrical box powering the transformer has no electricity
Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Electrical injuries. National Library of Medicine