Radio Parasitic Draw - How To Fix It

Today's car stereos do more than just play music - they are part of a sophisticated infotainment system that connects to your phone, provides directions, and does many other things. That's why they consume a significant amount of power from your electrical system and can also create a drain on your battery. 

If a battery drain occurs when the car is turned off, it's called a parasitic draw. This is when something in the car is still drawing power when it shouldn't. In many cases, that "something" is the car stereo.

This article will go into more detail about parasitic draws, including how to tell if your car's radio is causing the problem and how to fix it.

How To Tell If The Radio Is Draining The Battery

Radio wiring

If your car's battery is discharging while the car is parked, the electrical system has a parasitic draw, which means something is using electricity when it shouldn't. This parasitic draw can originate from many sources, but the most likely culprit is the radio. The reason is that most car radios are designed to work even when the ignition is switched off, drawing power whether or not the car is on.

Signs of a parasitic draw are similar to a bad battery and typically include:

  • The car struggles to start even with a new battery
  • Excessive engine cranking when starting the vehicle
  • Headlights, courtesy lights, and dashboard lights are dim
  • The battery warning light comes on frequently
  • The radio or other devices stay on even when they are turned off or the vehicle is turned off

You may not notice the drain if you drive your car every day. However, it could completely discharge the battery if the car sits for a week or even just a few days.

How To Locate A Parasitic Radio Drain

Test radio wiring

To locate a parasitic radio drain, first park your vehicle in a safe spot, preferably in the driveway or garage. Then turn the car off and check the following:

  1. Check all of the radio's wiring, making sure the connections are secure, and the wires are hooked up correctly. This can be done by taking apart the center console and examining the connections to the radio.
  2. Look at the fuse box. Using your owner's manual, identify the location of your radio's fuse or fuses. Ideally, the stereo is connected to a fuse that only draws power when the car is on.
  3. Using a multi-meter test tool, check for any electrical draw by grounding the tester and touching the stereo's connections.
  4. Inspect your car's battery to see if it's the right one and is rated for your vehicle. The battery info should be on the back of the battery.

If the battery is not the correct one for your vehicle, the problem may be as simple as replacing it. However, if one of the other things shows that the radio is using power, even when the radio and the car are turned off, then the radio is causing the parasitic drain.

ISS Automotive Can Help With Your Car's Radio

Repladement radio

Problems like the wrong fuse or a bad electrical connection are easy to fix. However, if the problem is with the radio itself, then it becomes a more difficult issue. Modern radios are made up of circuit boards, which are complex and hard to repair. That's where we can help.

In most cases, we can repair or replace your existing factory radio for less money than it would cost to buy a good-quality aftermarket one. There are several reasons why we recommend this approach. Not only is the design and fitment better on a factory radio, but the sound quality and integration are much better as well.

ISS Automotive has over 70 years of experience distributing and remanufacturing automotive electronic and mechatronic components. We offer a limited lifetime warranty on all remanufactured and repaired electronic products and provide free shipping on orders over $99. We've got a great selection of replacement radios you can easily order online here.

Contact us or give us a call at 800-548-1195 if you have questions or need help with your order.