Why does my car stereo lose its settings when I switch off the car?

If your car stereo loses radio presets, audio settings or other saved settings when you switch off the car, this is usually because the stereo is not receiving a permanent power supply from the car’s battery.

Most aftermarket stereos use two separate power connections:

• Yellow wire (BATT): Permanent 12 V used, among other things, to retain saved settings.

• Red wire (ACC): Ignition-switched 12 V that tells the stereo when to switch on and off.

In some cars, these connections are reversed compared with the stereo’s ISO harness. This occurs on some older Volkswagen and Saab models, among others.

How do I solve the problem?
Check that the yellow wire receives a permanent 12 V supply even when the ignition is off, and that the red wire receives an ignition-switched voltage.

Many car stereos have quick connectors on the red and yellow wires that allow the connections to be swapped.

Also check that the wiring harness is correctly connected and that no fuse has blown.

If the car uses CAN-bus, a specific adapter may be needed to obtain a correct ignition signal.

Can I join the red and yellow wires together?
This is not normally a recommended solution. If both wires are connected to a permanent supply, the stereo may remain active when the car is off, risking battery discharge.

Always follow the stereo’s installation manual and use the correct wiring harness for the car.

If the stereo still loses its settings despite a correct power supply, there may be a fault in the unit itself.

Contact our customer service team or visit one of our stores if you need help troubleshooting.