Smart Home Starter
The Smart Home Starter team picks the products and services we write about. When you buy through our links, we may get a commission.

How to Turn Off ADT Alarm System Without a Code

Last Updated Mar 30, 2022
Person pressing a button on their alarm keypad system.

A typical ADT security alarm system is between 100 and 115 decibels. Imagine standing next to a chainsaw, with the throttle wide open, in your living room. It’s loud. The neighbors will hear, and you can’t turn it off because you don’t have the code. Now what?

To turn off an ADT alarm system without a code—depending on the type of system—you have to do three things:

  1. Locate and remove the transformer plug from the outlet.
  2. Disassemble the security panel.
  3. Remove the backup battery.

There are other novel ways to turn off an ADT alarm that don’t involve acute panic and a baseball bat. While there’s no need to panic, there is an urgency to shut off the alarm. Neighbors may call the police, it’ll drive dogs crazy, and it may incur potential fines.

How to Turn Off Your ADT Alarm without a Code

There are several different ADT security systems, though all essentially follow the same routine. Many of the older versions have a panel box that’s separate from the keypad.

The panel box is where you will find the battery. After you’ve unplugged the transformer—a large, square plug that’s usually screwed into the power outlet—you’ll have to gain access to the panel box. If you live in a home with a previously installed system, the panel box may not be accessible through “traditional” methods, such as a key. Unless the previous owner or renter provided you with one, you’ll have to figure out a way into it to access the battery.

The battery is usually attached by two leads, similar to how 9-volt batteries attach to a plastic or rubber flap with both a positive and negative terminal. Disconnect it and, so long as you’ve unplugged the transformer, the alarm should stop. If you can’t locate the transformer, or it’s screwed in, the quickest method is to just cut the power from the circuit breaker, remove the battery, and then locate or remove the transformer.

Note: Some batteries will be located in the security panel itself, adjacent to the keypad, or directly behind it. There are several types of ADT home security systems, most manufactured by Honeywell, now known as “Residio.” All of these have a battery backup and draw their main power from an AC outlet.

Removing an ADT Command/Pulse Battery

The battery for the ADT Command and Control panel is located behind the touchscreen. Usually, you would use the touchscreen, select “tools,” enter your user code, and shut down the system. However, seeing as the user code is entirely meaningless in this situation, you’ll have to do it without bothering to shutdown first. You will need to remove a single screw, centered at the panel’s bottom, with a Phillips-head screwdriver.

Once the screw is removed, the entire touchscreen will slide up and off of the wall panel; once the touchscreen is separated, you can access the back. Behind the touchscreen, you will see the battery secured behind a plastic clasp with another screw.

Remove the final screw and pull back the clasp to get to the battery. The battery is attached to the panel through a quick-connect. Simply unplug the quick-connect, and then you can remove the battery.

Using the ADT Key Fob to Disable the Alarm

If the previous resident left behind an ADT security system, there’s little chance that the key fob will be lying around. If you own the ADT system, and your user code isn’t working, or you’ve forgotten it, the key fob will turn off the ADT alarm system without the code.

If you have the key fob handy, simply press “disarm”––sometimes a little shield icon with the diagonal slash––and your system will disarm; no extra steps necessary. Some key fobs require a two-second button press.

If the disarm button doesn’t work, hold the button down for two seconds instead. It depends on the system that is installed and the key fob that came with it.

How to Avoid Future ADT Alarm Triggers

Because a lack of a user code is the primary issue, avoiding potential alarm triggers should be your first order of business. There are a few ways to go about this:

Call ADT

Call ADT to inform them you are removing the hardware or seeing if they will send a technician. ADT equipment is leased to the owner when the alarm system is installed, and the lease extends throughout the entirety of the three-year contract. If you’re not the owner of the original contract or leased equipment, contact ADT to find out if they’ll send a tech to retrieve their equipment.

Remove the ADT Hardware

If you’re planning on removing all of the hardware, it is essential to contact the monitoring service to inform them, as mentioned above. If you are removing the old equipment, it may trigger an alarm, and the police would then be notified. This is a possibility even if the system is no longer officially being monitored.

If you’re allowed to take down the hardware yourself, always remove both the transformer and battery before taking down the control panel, sensors, and cameras. If you encounter wiring, be sure to cut the breaker switch.

Door and window sensors are usually installed with a silicone sealant. You’ll want to have some WD-40 handy to spray the silicone, soften it, and remove it with a scraper or putty knife.

If a sensor is wired, you will see the wires sticking out of the door or window frame after removing the contact and magnet. Disconnect the wires from the source, and you will usually be able to pull the wires out through the hole. (To learn more about how to remove your ADT window and door sensors, check out this article.)

Reset the ADT System and User Code

A security system will still function as an excellent alarm despite not being monitored by ADT. Suppose an existing ADT alarm system in your home belonged to the previous occupant or belongs to you and is no longer under contract. In that case, you can reset the system and replace the original user code.

This method generally works for Honeywell Alarm panels. Since most ADT panels are manufactured by Honeywell/Residio, this should cover the vast majority of security systems. The ADT Command panel doesn’t have an installer code, so it can’t be changed and should simply be disconnected.

Honeywell/Residio Alarm Panels

After removing the battery and transformer, wait 60 seconds before powering the system back on. After the system has rebooted, hold down the * and # keys until you are prompted to enter the installer code. Press *20 followed by whatever four-digit combination you choose followed by *99.

Now you can create a new master code. Enter your installer code followed by 802. You can now enter a four-digit number that will be your new master code.

Final Thoughts

Knowing how to turn off an ADT alarm system without a code is as simple as knowing where the battery is, where the transformer is, and how to remove them. Knowing which breaker switch to flip is essential as well. With alarms manufactured by Honeywell/Residio, you can take advantage of the security system as well.

The biggest thing is not to panic. An ADT alarm is extremely loud and will no doubt irritate your neighbors and their dogs. Being proactive and removing an unwanted security system will also help save you some headaches and avoid unnecessary alarms in the future.

Sign up for our newsletter
Smart Home Starter
This site is owned and operated by Time Off Club, LLC. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to This site also participates in other affiliate programs and is compensated for referring traffic and business to these companies.