Installing the VM-1 Voltage Meter

The VM-1 voltmeter allows you to monitor the voltage of your audio system or vehicle battery. The meter gives you a visual sign of voltage changes that could damage your audio components.

Choose a Mounting Location

The mounting location should:

  • Be easily visible from the driver’s seat to avoid driving distractions
  • Leave clear your view of the road and your vehicle’s gauges
  • Allow you to secure wires away from the vehicle’s controls to avoid any hazards while driving

Option 1: Mark screw locations using the included adhesive pad as a template. Secure the VM-1 with screws using the (2) mounting holes located under the front cover.

Option 2: Use the included double-sided adhesive pad. Clean the back surface of the VM-1 with rubbing alcohol. Wipe dry with a lint free cloth. Peel away the outer protective layer from one side of the adhesive pad and place it on the VM-1. Clean and dry the mounting location. Align and adhere the VM-1 to the mounting location.

Option 3: Flush mount your SQ VM-1. This advanced option involves permanently modifying the mounting location. You will need to cut an opening in an interior panel to accommodate the LCD display. Depending on the look and available space, you can secure the VM-1 however you would like. Be sure you can still reach the adjustment screw to calibrate the meter.


We recommend wiring the VM-1 directly to your car audio amplifier. To monitor battery voltage, you can wire to the battery.

This meter uses three wires:

  • Red is the 12V Constant wire.
  • Black is the 12V Ground wire.
  • Blue is the 12V trigger wire to operate.

Amplifier Install: Connect the red wire to the positive input on your amplifier. The black wire should connect to the ground terminal, and the blue wire should connect to the remote on.

Battery Install/Stereo Harness: If you choose to wire this to your battery, connect the red wire to the positive battery terminal. Next connect the black wire to the negative terminal. Finally, connect the blue wire to your remote turn on wire behind the dash (usually blue). The VM-1 should turn on with accessory power.

For direct connection to the stereo harness, first find your vehicles harness specifications. Locate the positive, negative, and remote (accessory) wires.

NOTE: If you connect the blue wire directly to your battery, it will stay on all the time!

Calibrate the VM-1 to your vehicle’s voltage

This step is required for precise, accurate measurements.

After you’ve installed the VM-1, read the voltage at your amplifier or battery using a digital multimeter. Remove the VM-1 front cover. Next, use a small screwdriver to turn the adjustment screw located above the LCD display under the front cover to match the reading from your Digital Multimeter.

Image of the VM-1 voltmeter with the cover removed to access the adjustment potentiometer Use a screwdriver to turn the yellow adjustment screw until the meter matches your reading of your vehicle’s voltage:

  • Clockwise – Voltage decrease
  • Counterclockwise – Voltage increase

CAUTION: Continued operation on low voltage could damage your amplifier or components.

Need Help? Contact us today with your tech support questions or any other inquiries.

Do-it-yourself car audio installation projects

Contact our customer support team by calling (405) 600-1936.
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