HomeWhatWhat Is ACC Power in Car: The Ultimate Guide

What Is ACC Power in Car: The Ultimate Guide

What is ACC power in the car?

Generally, the acc car electrics involve all electrical systems we use in some cars to power accessories like the lights, windshield wipers, and radio.

The system comprises a voltage regulator, an alternator, and a battery.

Surprisingly, the feature activates some car components without necessarily starting its engine.

This article provides more information about ACC power in a car. Let’s get started!

Table of Contents

Acc Electrical Meaning

It is a current type created when you connect two conductors in an electrical circuit.

In most cases, we also refer to it as an alternating current.

As the name suggests, this current is responsible for running ACC systems. 

(Car ignition lock close-up)

What’s ACC in a car? 

ACC stands for accessories. It is a position on the car switch that turns on accessories like interior lights, windshield wipers, and radios.

Unlike the on position that you can use to unlock all electrical functions on the car, ACC will only switch on the critical car functions.

Surprisingly, this feature turns on the car without turning on the engine. 

Most of the functions available in the ACC position will drain your battery.

Therefore, we recommend you understand your battery power and determine whether the ACC system will drain all of it. 

Windshield wipers

(Windshield wipers)

ACC Wire And Your Car Stereo

  • What’s The 12V Attachment Wire

Generally, your car stereo uses three power wires.

The 12V attachment line is red and links the vehicle’s ignition switch to the stereo. 

Turning on the car’s ignition will activate the 12V attachment line to turn on your stereo.

The 12V attachment lines should always be linked to power your car stereo.

If you remove your key from the ignition, the ACC wire will automatically lose power.

Consequently, the wire will shut down and, in the process, adopt the low-power mode.

Regardless of what you do, there is no accessory wire control, and your stereo won’t come on.

But how do you identify this 12V attachment line? Check out the next section below. 

Car audio picture

(Car audio picture)

  • Which Is The ACC Wire?

Although we already know the red wire is the 12V ACC wire, there are still other ways of identifying it.

Check them out below: 

Cars Having OEM Stereo

  • Firstly, set your digital multimeter at 12V
  • Secondly, secure your multimeter’s ground side in the dash
  • Thirdly, remove the radio so you to access the wires behind easily
  • Fourthly, set the car ignition to ACC and test the wires. A single wire must carry 12V. 
  • Next, turn off your ignition to remove the voltage.
  • Finally, return your key to ACC, and if the voltage returns, that should be the 12V ACC wire. Remember, the wire works only when you turn the ignition on. Also, it loses its power when you turn it off. 

Cars Having Aftermarket Stereo

  • Again, start by setting the multimeter at 12V
  • You’ll carry out your test at the ignition harness or fuse box
  • At this point, you should secure the tester’s ground side in the dash
  • Next, activate the car ignition and test the wires in your fuse box or ignition harness. One wire should at least record 12V. 
  • You can then deactivate the ignition, and the voltage will disappear
  • Finally, activate the car ignition, and if you note the voltage return, that is the 12V ACC wire
A photo of a multimeter

(A photo of a multimeter)

  • Wires Powering Stereo System

Depending on your car type, at least two to three wires help power your car stereo system. 

  • First, a 12V wire powers the clock and keeps the memory alive. This wire is always hot since it functions whether your vehicle is off or on yet retains the 12V.
  • Second, we have a red 12V ACC wire which is labeled ACC. This wire turns on the car stereo system. However, it only works when your vehicle runs or the ignition is on. 
  • Finally, we have the illumination or dimmer wire. This wire is orange with some white stripes. It helps to power the dash lights and headlights. Therefore, it makes the headlight or dash light shine brighter or dim. 

(Car headlight)

What Do The Accessory Fuse Control?

We use the accessory fuse to control the ACC power sockets.

Generally, these sockets power when the car ignition is on, and we use them to power different accessories like GPS devices and phones. 

Also, switches and circuit breakers on the electrical panel are labeled with ACC, standing for accessories.

You can find the accessory relay on the driver’s end of the fuse box or dash relay.

The relay protects the car’s NAV system, relay power sockets, and other circuits like radio. 

Furthermore, the eighth fuse on the driver’s side protects the car’s NAV system, power socket relays, and other components.

If this fuse is damaged, the ACC won’t operate the sound system, power windows, and climate control. 

Automobile fuse

(Automobile fuse)

Will The Battery Drain When You Leave Your Car In ACC Mode?

After enabling accessory mode, you turn on electrical accessories.

Surprisingly, electrical accessories don’t use up the car battery and thus don’t drain it. 

Generally, the accessory mode lets you run your car’s electrical components, like power windows and navigation, without turning on the engine.

However, you might sometimes activate high power-consuming components like ventilators, defrosters, and headlights during ACC mode. Such components might result in battery life loss. 

Fortunately, when your battery gets used up, you can start the vehicle engine to recharge it. 

A mechanic replacing car battery

(A mechanic replacing car battery)


As highlighted, ACC stands for accessories and represents a position on the car switch that turns on some accessories.

The ACC model allows you to run your car’s electrical components without turning on the engine.

Some components you can operate include power windows, an audio system, and navigation. 

We hope this article has been helpful, and if you have more questions, contact us. 

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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