Bluetooth module for an old Sony CDX-3002 radio
And when I first connected it to the car, something started smoking inside. The Bluetooth module burned out. I started to determine the cause. And... It turned out the 7805 Crankshaft was faulty. This is a 12- to 5-volt converter. But it was outputting 12 volts, not 5. That's why the module burned out. The good one burned out. Now I've installed a worse one. And a new Crankshaft. Everything works. But... There's a slight beep. Background. And Bluetooth is constantly on. You need to connect the ignition to the lock so that the red wire goes to the radio. Then it will turn off! Otherwise, it sounds fine from Bluetooth!