The Pioneer Light Green parking brake wire does NOT connect to anything in the car’s factory harness. It connects to the metal switch on your parking brake assembly (the side that sees ground when the brake is engaged).
This "alternator whine" that changes pitch with your engine's RPM is almost always a symptom of a poor ground connection. Double-check that your black ground wire is securely attached to a clean metal part of the chassis. Pioneer Avh X3600bhs Wiring Harness Diagram
For the included Bluetooth calling microphone. The Pioneer Light Green parking brake wire does
Must detect a ground signal to unlock video playback, Bluetooth pairing menus, and advanced settings. Double-check that your black ground wire is securely
When you shift into reverse, the 12V from the reverse light will trigger the Pioneer to switch to camera mode instantly.
This wire is used to trigger external devices. Connect it to the remote turn-on terminal of any external power amplifiers, or to an auto-antenna relay control terminal. Crucially, this wire should not be connected to the power antenna wire if you have a standard antenna that extends; use it only for amps or amplified antennas. It provides a maximum of 300 mA at 12V DC.