How to Adjust a Viper Car Alarm

by Paul Saucier
George Doyle/Stockbyte/Getty Images

How many times have you awakened to the sound of your Viper car alarm at 3 a.m., only to find that it was the neighbor's cat jumping on the hood of your car? Or maybe it's a passing garbage truck, or a booming stereo system from the kid down the street. Viper makes great alarms, but like every other alarm on the market, sometimes they just need some adjustments.

Step 1

Find the location of the shock sensor. Start by looking under the driver's side dashboard of your vehicle for a small black or clear box, usually no more than 3 inches square. The exact location of this module depends on where the installer placed it. Although no two vehicles will be the same, Viper recommends using wire ties to secure the module to a large bundle of wires. If the sensor is not easily visible or accessible from underneath the dash, some disassembly of your vehicle may be necessary. Start by removing the knee bolster (the panel under the steering column). The exact processes and tools needed will depend completely on your vehicle.

Step 2

Look for a small knob or inset screw along one side of the unit. This will be the adjustment dial. Using your finger (if possible) or a small flathead screwdriver, turn the dial clockwise to turn the sensitivity up, and counterclockwise to lower the sensitivity.

Step 3

Test the sensor by slapping several areas of your vehicle with a flat hand with fingers slightly spread (do not use a fist, and make sure to remove any rings -- you don't want to damage your car). At minimum, check the sensitivity on the four corners of the vehicle. Adjust the sensitivity again if necessary.

Reassemble your vehicle if necessary.


  • Alarm shock sensors respond to impact and vibration only. Kicking the tires or rocking the car while standing on the bumper is not a good way to test the sensitivity. Many alarms have a "dual stage" sensor that emits a short chirp on lighter impacts and triggers the full siren on heavier impacts; keep this in mind while testing and adjusting. When searching for the alarm components, take a quick look under the dash before you disassemble anything. Many installers will make the shock sensor fairly easy to get to in case adjustments need to be made after installation.


  • If you must disassemble your vehicle for access to any of the alarm components, use caution. Some vehicles have knee bolster airbags that must be removed, and nearly all vehicles will have airbag or high current wires near the area in which you will be working. If in doubt, ask a local professional to do the work for you.

Items you will need

  • Screwdriver and socket set

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