an amp to perform perfectly when the key is in the acc. position, but the second i turn the key to the run position (without even starting the car) a terrible hum starts comming thru the speakers. if i start the car, it still does it regardless of engine speed, heater speed, anything. it's not like alt whine at all, just a steady humming sound. i tried different rca's, even had the amp sitting on the seat, and nothing would remedy it. as soon as i shut the car off, or just return the key to the acc. position without starting the car,,the noise stops. btw my car has the type of ignition where the key doesn't turn backwards,,,it just goes from off/acc/run/start....if that helps.

 

Try powering your HU from a seperate 12v source and get back to us on what happens with the engine running...

 

As Dereck said an item that starts when the ignition switch is in the run position (fuel pump, ventilation controls, warning relays, etc.)is probably the issue or even the ignition switch (unlikely). Run with Haunz recomendation.

 

it may be, but i already have an amp hooked up to that same location(it's in my winter car), and i just wired this other one to test it and the noise started. the other amp, a really cheap amp i might add, has no problems. i don't really have another power source i could use to try what haunz said.

 

^ Beg/borrow/steal a 12v battery or a computer powersupply... [img]graemlins/dunno.gif[/img]

 

^^^i got a pc power supply,,,i never thought of that. i will give that a try.

 

What about a daytime running light module, could that be an issue?

 

well i hooked it up to a batt. charger and it still makes the noise. i took another identical amp and hooked it up to the charger and no noise?? [img]graemlins/dunno.gif[/img]