• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Precision Audio & Tint

Thomasville: (229) 233 5001Bainbridge: (229) 246 2111
  • NEW! SHOP ONLINE
  • Financing/Lease to Own
    • Easy Payments, No Credit Needed
    • $0 Down, 0% APR Financing
  • Our Work
  • Reviews
  • Facebook
  • Instagram
  • Request a Quote
  • About Us
    • Why Choose Us
    • Hours and Directions
    • Our Facilities
    • Virtual Tour Bainbridge Store
    • Virtual Tour Thomasville Store
    • Work for US
    • Gift Cards
    • Contact Us
  • Services
    • Car Audio
      • Backup Safety
      • Mobile Video
      • OEM Integration
      • Professional Installation
      • Smartphone Integration
      • Vehicle Navigation
    • Marine Audio
    • Motorcycle Audio
    • Remote Starters
    • Wheels & Tires
  • Window Tint
  • Customize Your Truck
    • Bed Covers
    • Floor Liners And Accessories
    • Grille Guards And Bumpers
    • Hitches
    • Leveling and Lift Kits
    • Jeep Parts And Accessories
    • Step Bars And Running Boards
    • Toolboxes
  • Brands
    • JL Audio
    • Kenwood
    • Pioneer
    • Fuel Wheels
    • Llumar Window Tint
    • Rockford Fosgate
    • Cam-Locker
    • Ranch Hand
    • Rough Country
    • WeatherTech
You are here: Home / ARTICLES / Tools of the Trade – The Digital Multimeter

Tools of the Trade – The Digital Multimeter

By BestCarAudio.com Leave a Comment

Digital Multimeter

Our continuing look at the tools a mobile enhancement technician should have at his or her disposal brings us to the ever-important digital multimeter. In the same way that an RTA or oscilloscope is needed to measure and quantify alternating-current signals, a high-quality multimeter is the only way to accurately quantify a DC or fixed-frequency AC signal. Read on to find out how technicians use their digital multimeters (DMM) to test the wiring in your car to make the installation process more accurate.

What Is a Digital Multimeter?

In essence, a DMM is a battery-powered, handheld device with a digital display that can perform several measurements. A DMM is occasionally (but rarely) called a Volt-Ohm-Milliammeter (VOM), giving us some insight into its capabilities. In almost every case, the meter will have between two and four terminals at the bottom for the connection of the test leads and an LCD or VFD (vacuum fluorescent display) screen at the top of the unit to show the measurement reading. Some of these displays include an analog bar graph that can be used to help detect transient signals. Finally, the function selection is made by a rotary control in the middle of the unit.

Digital Multimeter

Most units will measure direct current (DC) and alternating current (AC) voltages to either detect or quantify the presence of voltage on a terminal or wire. Meters separate the DC and AC measurements into different functions as some math needs to be applied to the AC measurement to create an RMS value. Premium meters known as True-RMS systems are more accurate when measuring AC signals outside of the 50-60Hz frequency region.

Multimeters can also measure resistance. They perform this task by feeding a very small amount of current through a device (resistor or circuit) and measuring the voltage drop across a fixed resistance value. DMMs are good at measuring resistance above an ohm or two and up to about 50 megohms. Below 1 ohm, the resistance of the cables and connections becomes an issue.

Finally, most meters can be used to measure AC and DC flow. The meters have an internal shunt resistor that is wired in series with the circuit. The voltage produced across this shunt resistor is converted to a current flow measurement. The test lead connects for current measurements are different than those for voltage and resistance readings.

Digital Multimeter
An old analog multimeter from RadioShack. While still great for some measurements, analog meters should not be used to test circuits in modern vehicles with data systems or airbag wiring.

How Technicians Use a DMM

When you are having a remote car starter, security system or even a new radio installed in your car or truck, the technician will use a multimeter to test the wires in the dash for the presence of voltage. In almost all cases, the tech needs to find a good ground, a constant power source and a switched (or accessory) source to feed and control the device.

Resistance measurements come in handy when testing speaker wires or terminals on a subwoofer enclosure to estimate the impedance of a speaker. For techs who are installing remote starters on older General Motors vehicles, they use the ohmmeter function to measure the value of the Passlock resistor in the key. It’s worth noting that the ohmmeter in a DMM can’t be used to test the suitability of a ground connection accurately. A proper grounding point should have well under 0.01 ohms of resistance.

Digital Multimeter
DMMs aren’t good at measuring very low resistances. This image shows the resistance of the test leads and connections using a good-quality Fluke digital multimeter.

Finally, taking current measurements is ideal for troubleshooting situations where car batteries are being drained. If you have a situation where your car battery is dying after a few days, the technician can measure the current being drawn from the battery to start the diagnosis and repair process.

Digital Multimeter
D’Amore Engineering in Camarillo, California, offers the AMM-1. This meter is designed specifically for car audio technicians and includes AC and DC voltage measurement, maximum and minimum DC voltage readings and incredibly accurate amplifier power measurement capabilities.

Choose the Right Mobile Enhancement Retailer

As we’ve mentioned in the past, choosing the right person to work on your vehicle is the most important aspect of the upgrade shopping process. A moderate-quality upgrade that has been installed and configured correctly will undoubtedly outperform a premium product that hasn’t been installed with care. When you tour the shop as part of your retailer interview process, make sure they have the tools required to perform the work you need. At the top of that list of tools is a quality digital multimeter.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Share this:

  • Click to share on Facebook (Opens in new window) Facebook
  • Click to share on X (Opens in new window) X
  • Click to share on Pinterest (Opens in new window) Pinterest
  • Click to email a link to a friend (Opens in new window) Email

Filed Under: ARTICLES, Car Audio, RESOURCE LIBRARY

About BestCarAudio.com

BestCarAudio.com is a showcase for the very best mobile electronics retailers in the world and a place to educate and inform interested consumers about existing and emerging technologies.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Search our Articles and Installs

Recent Customer Review

Request a Quote
Car Audio

Car Audio

Precision Audio & Tint in Bainbridge and Thomasville are truck and car audio upgrade specialists. Whether you are interested in adding Apple … Read More »

Tags

2015 2016 2017 2018 2019 2020 2021 2022 Amplifiers Android Auto Apple CarPlay Bed Covers Camlocker Chevrolet F-150 Ford Fuel Fuel Wheels GMC Grille Guards Hunter Road Force Jeep JL Audio Kenwood Leveling Kits Llumar Nitto Pioneer Radios RAM Ranch Hand ReadyLift Rockford Fosgate Rough Country Speakers Step Bars Subwoofers Toolboxes Toyota TrailFX Undercover WeatherTech Westin Window Tint Wrangler
A happy man driving a car down the road while music notes float by in the breeze

How to Shop for a Car Audio System with Future Upgrades in Mind

 By BestCarAudio.com Leave a Comment

Upgrading your car audio system is an exciting journey. Many car owners start with basic improvements but soon find … [Read More...]

Expert Tips for Upgrading Your Boat’s Stereo System

 By BestCarAudio.com Leave a Comment

There’s nothing quite like spending a sunny day out on the water, and having the right soundtrack only enhances the … [Read More...]

The-3-Most-Important-Speaker-Parameters-and-Why-You-Should-Care-Lead-in

The 3 Most Important Speaker Parameters and Why You Should Care

 By BestCarAudio.com Leave a Comment

When you’re upgrading your car audio system, selecting the right speakers involves more than just brand loyalty or power … [Read More...]

The 3 Most Important Speaker Parameters and Why You Should Care

 By BestCarAudio.com Leave a Comment

Saving money feels good. Until it doesn't. Whether it’s a bargain-priced amplifier or a budget installation from someone … [Read More...]

A man sitting in his car driving down the highway glancing out the window

The Safety Net You Didn’t Know You Needed: Aftermarket Blind Spot and Collision Warning Systems

 By BestCarAudio.com Leave a Comment

If you’ve looked at a new vehicle lately, chances are it included some type of advanced safety feature like blind spot … [Read More...]

Bainbridge Location


Get Directions to Precision Audio's Bainbridge Location
Address:
909 Dothan Road, Bainbridge, GA 39817
Phone: 229-246-2111
Secondary phone: 229-246-3888
Email: salesstaff@precisionga.com

Opening Hours:
Monday : 8:30 am – 5:30 pm
Tuesday : 8:30 am – 5:30 pm Open Now
Wednesday : 8:30 am – 5:30 pm
Thursday : 8:30 am – 5:30 pm
Friday : 8:30 am – 5:30 pm
Saturday : Closed
Sunday : Closed

Thomasville Location


Get Directions to Precision Audio's Thomasville Location
Address:
12588 US Highway 319 N., Thomasville, GA 31757
Phone: 229-233-5001
Email: thomasville@precisionga.com

Opening Hours:
Monday : 8:30 am – 5:30 pm
Tuesday : 8:30 am – 5:30 pm Open Now
Wednesday : 8:30 am – 5:30 pm
Thursday : 8:30 am – 5:30 pm
Friday : 8:30 am – 5:30 pm
Saturday : Closed
Sunday : Closed

MESA retailer

Copyright © 2025 Precision Audio & Tint · Privacy Policy · Website by 1sixty8 media, inc. · Log in