How to Disconnect a Car Alarm

Your car alarm is a safety feature that helps deter thefts while your vehicle is not under your watchful eye. Most function by detecting suspicious activity such as the locks being tampered with, windows being broken, or mismatched chip keys being used to try to start the car. Unfortunately, even good features sometimes go bad over time and become more of a nuisance than a helpful aspect. They may cause a ruckus at inopportune times, make your vehicle a target for theft or vandalism, or even completely disable your vehicle making it impossible to drive. This article will help you figure out different ways on how to disconnect a car alarm.

Method 1: Things you will Need

  • Wrench;
  • Owner’s manual;
  • Wire Cutters;
  • Protective items including gloves and eyewear.

Method 1: The Steps

  1. When working on vehicles and learning how to disconnect a car alarm, always take precautionary measures to protect yourself from injuries. It is a good idea to wear safety gloves and protective eyewear, especially when working with electrical components.
  2. Park your vehicle on a sturdy, flat, dry surface.
  3. Raise the hood and securely prop it up with the hood post.
  4. Use the wrench to disconnect the negative cable from the vehicle’s battery.
  5. The next step for learning how to disconnect a car alarm is to consult your owner’s manual for a fuse box diagram if the alarm you are removing is a factory installed one. There you will need to find the fuse for the car alarm. Next, you will need to remove that car alarm fuse from the slot in the fuse box. If the alarm you remove is an aftermarket product, the fuse will likely be underneath the steering column and wired into the alarm. Removal of the fuse in most cases will deactivate the alarm.
  6. Next, locate the main box of the alarm. You will need to follow the wires leading from the alarm and disconnect all the wires clipped to it. You can clip away the wires hard-wired into the main alarm using the wire cutters. Make sure all the wires you cut or pull lead only to the main alarm circuit.
  7. Once you remove all wires, you can reconnect the negative cable to the car battery.
  8. The final step is to give it a test to be sure you had disabled it fully. Hit your fob to see that you cannot enable it or get it to sound when you press the panic button. If you find the vehicle cannot start, or that the alarm is still functioning, it is likely because you had cut a wire you shouldn’t have or, there is still a wire that you need to disconnect from the system.

Method 2: Things you will Need

  • Wrench;
  • Owner’s manual;
  • Wire Cutters;
  • Protective items including gloves and eyewear;
  • Screwdriver;
  • Wire crimper;
  • Electrical tape.

Method 2: The Steps (Aftermarket Alarm)

When working on automobiles and educating yourself on how to disconnect a car alarm, always take preventative measures to guard yourself against injury. It is a necessary step to wear safety gloves and protective eyewear, specifically when working with electrical modules.

  1. Park your car on a solid, level, dry surface.
  2. Lift the hood of the vehicle and securely keep it in place with the hood support.
  3. Locate the car battery to disconnect the negative cable by turning the bolt that is fastening it to the battery counterclockwise.
  4. Remove the interior plastic door panel on the bottom of the driver’s side of the car. Use the screwdriver to pry it off by pressing any plastic tabs inward and release it from the door frame.
  5. Look for the alarm box behind that panel. It will likely be a small box with a single antenna protruding from one of its sides. Use your wire cutters to remove it by cutting away any zip ties, wires, brackets, or cables that are holding it in place or connecting it to the alarm system. The wires will connect the alarm to the ignition, horn, lights, and locks. Once you cut and disconnected everything, you can completely remove the alarm box.
  6. Repair the ignition wires by matching the two wires in the door to the two wires that lead to the ignition. You will want to match up the colors of the wires to each other. These are the original connections that had to accommodate the alarm so that it was inline. Re-attach the wires together using a wire crimper and wrap it securely with electrical tape. Replication this process for the wires that connect to the horn, lights, and power locks.
  7. Replace the plastic door panel. It should pop right back into place.
  8. Reconnect the negative battery cable to its post using a clockwise rotation using your wrench.


When functioning properly, a vehicle’s alarm system is a terrific feature to have that helps protect your investment from theft and damage. However, over time it may become unreliable and cause problems like creating noise by going off unnecessarily or by not allowing your vehicle to start. This may cause you to wonder how to disconnect a car alarm. Luckily, a lot of times it is an easy procedure to handle on your own. With a little effort, you can remove your alarm and keep on driving.

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