How can I check the voltage supply to the stereo in my car?

Answer by  nvsikka (7)

It will be Red and Black wire. The red is positive and the black is negative. Take a multimeter and rotate its voltage range in DC.20 Voltage range is enough.Touch multimeter's Red wire with Stereos Red wire and Black wire with balck wire. Then switch the car on.Then it will show the voltage, its normally 12V.

Answer by  eyeguy (3760)

With a simple 5 dollar voltmeter from the dollar store. It has to clips which you connect to the power wire , usually red, and the other clip to something metal. The device will read the volts instantly.

Answer by  hobominer (184)

you can check two places depending on your car stereo setup. you will need a multimeter - check either the positive (usually red/colored) wire coming from the back of the fuse that is labelled radio (car fuse box) or directly to the back of the stereo itself (may require removal of the unit for access).