How to Find the ACC Wire in a Car?
2 Answers
Car ACC wire is located in the car's fuse box. Here are the specific methods to identify the ACC wire: 1. Turn off the power: Open the car's fuse box and turn off the vehicle's power supply until the dashboard lights go off. 2. Test with a circuit tester: Locate the yellow fuse inside the fuse box and test it with the tip of the circuit tester to check if the circuit has power. 3. Light indicates ACC wire: When the vehicle's power is turned on, if the yellow fuse lights up on the circuit tester, it can be confirmed as the ACC wire. Here is additional information about car electrical systems: 1. Power on at ACC position: The ACC wire is the ignition power line, connected to the key-controlled ACC power supply. When the key is in the ACC position, meaning the ACC wire is connected, some electrical devices in the vehicle receive power, such as the radio and audio system, while other components remain without power. 2. Power off at LOCK position: When the car is parked and turned off, and the key is in the LOCK position, the vehicle's circuit is disconnected, cutting off all power, and the steering wheel lock will engage. When the key is in the ON position, all components of the vehicle are powered, including the engine system. The START position is for ignition; once the key is turned to the START position, the starter motor receives power and begins operation.
I remember when I used to look for the ACC wire myself, I usually started near the ignition switch under the steering wheel because there was a bunch of wiring harnesses connected to the keyhole. When the key is turned to the ACC position, the wire should carry 12V voltage, and I could test it with a cheap multimeter. The most common colors are red or yellow with stripes—for example, Japanese cars often use blue wires, while American cars tend to use red and black wires. The fuse box is also a good place to look; many models hide it behind a cover under the driver's seat. After opening it, I checked the labels for the ACC marking. Safety-wise, I always had to be careful—first disconnecting the negative battery terminal to prevent short circuits, as sparks could blow a fuse or damage the car's wiring. Once found, installing accessories became much easier, like directly wiring an additional USB charger or dash cam, greatly simplifying daily use and avoiding extra wiring. Experience tells me that differences between brands can be significant, so checking the car's manual or online community posts can save a lot of time.
