Car Unit Wired to All ACC Power?

[lordcupkake]

Okay, so the situation is as follows: I had a factory stereo. Said stereo stopped working when I accidentally connected the battery backwards. The fuses are all fine (have been checked and replaced). The radio still does not get power. I have removed the factory radio and plan to put in an aftermarket stereo that I got off cragislist (this thing works, I've hooked it up straight to the battery and it's all good.) However, the factory power connections no longer deliver power to the stereo (assuming there's a short/break in the wire somewhere). Regardless, now I need to connect to radio to power from something else (i.e. sacrifice the cigarette lighter.)

My plan was to disconnect the power from the cigaretter lighter and connect this to both the ACC and Battery wires on the stereo. As far as I can deduce, the only downside here is that the cigarette lighter is now inoperable (not really a loss because the stereo has a USB port) and that the radio will not be able to save presets as it will lose ALL power when I take out the keys. Am I missing anything? Any better suggestions? Keep in mind I am trying to go as cheap as possible here because my car is old and I also am very inexperienced with electrical stuff. Thanks in advance.

Click to read more...

 

[Skydronaut]

You should use a multimeter (it's easy to find a really cheap one for this kind of application) to measure resistance in the positive and negative lines in the wire harness for your h/u. These should give near-zero ohm readings. Either your power or ground can be shot. If they are both reading low resistance, you are going to need to check for power with the multimeter- connecting the positive and negative wires to your multimeter in DCV mode. Shouldn't get more than 14ish volts with the car running.

I do not recommend hooking up an aftermarket stereo to your cigarette lighter power and ground wires! I don't know your car's electrical schematics, but the wires for that component likely aren't the proper gauge for a power-******* device like an aftermarket h/u. How many amps are you planning on drawing with your aftermarket h/u? Also, the lighter fuse most likely is the wrong value (if it has its own fuse, that is).

 

[bump465]

if youre sure the radio works then I would suspect you hooked up your remote wire wrong. get a multimeter and find the 12v cable that is on when your car is on and off when car is off. You will not need to worry about loosing settings when you turn your car off because the unit will also be hooked up to a constant 12v source.

If you ONLY plan on powering this radio you can use your cigarette lighter. I wouldnt because its tacky and i hate breaking things to get others to work. your radio puts out maybe 10-20 watt per channel so you will only need a 5-10 Amp fuse. stock vehicle wiring can handle this load.

If you plan on hooking up an amp to power the speakers do NOT use the cigarette lighter. No matter how weak the amp is, it will pull waaaay to much power from your cigarette lighter.

 

[Chris McNeeley]

Or just wire it direct to the battery, put a relay on the power line, and use a wire from your cigarette outlet to to open and close the relay as the car turn on and off.