s13 240sx power problem???

[1992s13hatch]

I am having a problem with my 93 hatch. when ever I have my key turned to the on position and turn my lights on then I hit my brakes the lights go deem and my radio turns off. It also happens when I turn on my high beams does any one have any clue what this could be. I checked my grounds and they all look fine open to any thoughts

[Mishkin_707]

Alternator is probably on it's last leg, get a voltmeter and check voltage, or start your car, then disconnect the positive battery terminal, if the car dies you need a new alternator

[240sx9406]

bad battery bro! check the battery cells acid or take to autozone for a free battery check

[1992s13hatch]

I was thinking it was the battery

[1992s13hatch]

I'll check out the alt to

[claytoncallihan]

Power issues usually come in three's just a heads up (usually battery, alt, and starter) although you may get lucky. Usually you at least have the alt and battery messing each other up and end up needing at least both of those. I would check it out asap before it gets worse.