How to Disconnect an Auto Alarm

You may have to disconnect your car alarm if you cannot shut it off.

Car alarms occasionally malfunction, annoying their owners and others in the vicinity. It's useful to know how to disable the alarm rather than to have to call and wait for a mechanic or alarm specialist.

Car alarm circuits vary but generally toggle switches that disconnect the alarms are installed on dashboards or nearby. Many alarms allow you to disable them with remotes. Malfunctioning alarms might just need new batteries. A broken wire also might be the culprit. If these are not solutions, then it is probably time to work manually on your car alarm.

Things You'll Need

• Screwdriver
• Safety gloves

Instructions

Disconnecting Your Alarm

1. Open the hood of your car. Find the line connected to your car's battery that runs to the alarm system. Disconnect it from the battery. It typically has a fuse attached close to the positive battery post. This will disable the alarm and allow you to work freely without the alarm sounding while you are trying to disconnect it.

2. Unplug all of the switches in the "brain box," which is typically black and installed under the dashboard near the steering wheel. All of the circuits are linked there, including the alarm wires and relays.

3. Unplug the two wires attached to the ignition system. These wires are under the steering column and run up to the back of the ignition switch. Be careful not to disconnect the actual ignition wires for the car; you are disabling only the wires that run from the brain box to the ignition. They generally are more fragile-looking than the stock wiring.

Tips & Warnings

• The key to understanding how an auto alarm system can be disconnected lies in understanding how the alarm system works. As soon as you try to open the car door without the remote, the starter and fuel pump are disabled. This can be solved by introducing a series of resistors after measuring the resistance on your remote using an ohmmeter. The resistors you introduce should measure up to the same amount as that of your remote. Then identify the hot wire and cut its power source to disable the alarm.

References

• Hornet: Users Manual