Damm audio problem.

Discussion in 'OT Technology' started by NetChemica, May 31, 2004.

  1. NetChemica

    NetChemica OT Supporter

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    Alright, so I have an aging 87 BMW 325es. Starting about a month ago, whever I would hit the brakes (when the rear lights turn on), my radio would stop playing as if I hit a big pothole. That slowly progressed to me using anything electronic like turn signal, wipers, lights, fan, or opening the door. Now the radio wont even turn on at all. I tried putting in my friends radio (he also has a sony) and I got the same symptoms. Any idea what that could be?

    cliff notes: my radio used to turn off when i used anything electrical, now it doesnt work
     
  2. 04

    04 Guest

    Do you have a Multimeter?
     
  3. percent

    percent deluded

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    sounds like something fishy in the whole electrical system. But as far as i can tell the main problem is not getting power. Solution: bypass the current electrical system and go straight to the battery (no its not dangerous if you do it right, technically it should already hooked to the battery, but the stock wires are routed all over the place). Anyway figure out which wire is the constant power (if its an aftermarket radio it is almost always yellow, if its stock youll have to look it up).

    Cut that wire and rerun a 12-14 guage or so wire directly to the battery (there may already be a place in the firewall to squeeze through or you may need to drill a little hole - im not real familiar with bimmers inparticular). Then try the radio. If it works, great. If not then there is a problem with the 12v accessory power (usually red on aftermarket decks, stock - ??) To solve this: cut that wire and run it to a power wire you know works that is on only when the car is on (cigarette lighters are often a good choice).

    Like the first guy said. If you have a multimeter (you can find one for like $7 at home depot or walmart or most places that have any kind of home repair or car repair section.) You can test the voltage coming from each of those wires and see which is bad before you run anything. everything should be in the 12 volt range +- 3v or so.

    As far as why its not working - my thought is that there is some problem with the wire somewhere in the car. Either a short or physical damage or bad connection - these things just kinda happen after years of use
     
  4. Tamedgerbil

    Tamedgerbil Guest

    (BTW, I'm NetMechanica posting at my friends house, so :fawk: )

    Well, I ahve a multimiter. My batter is in the trunk of my car and I tested the leads in the hood of my car (dont know if they are direct or not). When I tested it I got 12.5x volts with the car and everything off, 11volts with a bunch of items running and the car off, 13v with the car running (didn't matter if things were running or not).
     
  5. percent

    percent deluded

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    those voltages seem fine, but you want to test to one that is running in the head unit - right where it goes in. So if you can unplug the head unit and test the power coming through there, thats what you want to know (some searching might be able to provide you with wire colors, or just test until you find two that give up positive voltages (well if your having the problem you talking aout one may not be working).
     

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