What are car stereo wiring color codes for a 2001 Volvo S40?

For a 2001 Volvo S40, the car stereo wiring color codes typically include the following: the constant power supply is usually a red wire, the ignition power is often yellow, the ground wire is black, and the speaker wires are color-coded as follows: front left (+) gray, front left (-) gray/black, front right (+) white, front right (-) white/black, rear left (+) green, rear left (-) green/black, rear right (+) purple, and rear right (-) purple/black. Always consult a wiring diagram specific to your vehicle for accuracy and safety when making connections.