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Discussion Starter #1
I have a 91 GSM. The batter charges fine while driving and will start up unless it sits for a longer period of time, in which case the battery dies. I replaced the battery, and this did not solve the problem. The alternator checks out fine.

I also notice a buzzing noise when the radio is turned on especially when tuned to low frequency stations. Could the radio have a short? If so, how can I find/fix that?

Thanks in advance.
 

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You have a short somewhere causing a parasitic drain.

Easiest way to test for it is too watch the voltage at the battery with the car off and pull fuses until you no longer see a loss of voltage. That narrows the problem down to that circuit somewhere.
 

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Discussion Starter #3
Thanks..Do you think the voltage change will be noticible using an inexpensive analog volt meter?
 

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If you recently put in a cd player, check all those wires especially your ground wire.
 

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Discussion Starter #5
I don't have a CD player, although the radio makes a buzzing sound; however, I don't think the radio has the short.
 

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I know this might sound kinda dumb but you wouldnt by chance have your cell phone on you when you hear that sound. My cell makes my speakers go crazy when its in certain areas of my car, even when its not running.
 

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greenstreak said:
You have a short somewhere causing a parasitic drain.

Easiest way to test for it is too watch the voltage at the battery with the car off and pull fuses until you no longer see a loss of voltage. That narrows the problem down to that circuit somewhere.
Good Advice

The bad news is (unless a deep cycle battery) that the battery loses some capilbility every time it is drained, espically the first complete drain :(
 

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Slownis said:
No. Its not alternator related if it drains while its just sitting there.
an alt thats shorting to ground WILL cause a leak because its allowing current to flow , which causes heat, which uses power ...

pull your ecu fuse first, because all ecu's use power when the car is off, then pull the radio fuse because the same applies to that .... work from there

migth be best to pull one of the battery cables, and use the volt meter to connect the battery to the clamp, that way all the power being used goes straight thru the meter. allowing a more accurate test of the power being used, instead of trying to atch for a gradual power drop
 

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hotrodkid said:
migth be best to pull one of the battery cables, and use the volt meter to connect the battery to the clamp, that way all the power being used goes straight thru the meter. allowing a more accurate test of the power being used, instead of trying to atch for a gradual power drop
I have to jump in quick.
Running a voltmeter inline like described above can be dangerous if done wrong. First of all, you will be measuring amps, not volts. Leave the multimeter's selector on volts and you may toast the meter. Even the higher priced multimeters are only good up to 10 amps so DO NOT even think about starting a car with a meter hooked up this way. Luckily, they have internal fuses (don't ask me how I know :eek: I really have to give up smoking crack ;) ) Actually, I've been in electronics for over 20 years, man I'm getting old.
If you follow the above, I recommend hotrodkid's way. You will see in milliamps how much draw you car (IN THE OFF POSITION) has which will indicate if you even have a high draw. Also, like GreenStreak said, when you pull fuses you will see a big change in milliamps when you find the culprit. Happy hunting :)

If unsure of what you are doing, please go to a place and have them check it out. Batterys can explode and they are filled with acid, be safe
 

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Also, if you are going to put a voltmeter inline with the battery (set on Amps), do it on the negative terminal, and use a jumper wire first. With the jumper wire connecting the ground to the batt terminal, connect the leads on the voltmeter in parallel with the jumper, then remove the jumper wire and take your reading. This will prevent spikes which can damage your meter or electronic components in your vehicle. As has already been stated, if you are unsure go to a pro and let them do it as it can be dangerous. Good luck.
 

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My 92 would drain also. The ECU would not turn off the realy after the 8 second delay. Listen for that the relay click below the radio after you turn off the key. You could remove the MPI fuse at the + terminal to stop the drain if thats it. Use a simple test light between battery ground post and ground wires to test for a drain, light should be out with no current drain. AutoZone-AdvanceAuto could test your battery and alternator free.
 

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Discussion Starter #16
Thanks, The relay should "click" 8 seconds after turning off the vehicle? If that doesn't happen, then it's probably the ESM staying on, right?
 

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Yes.
The ECU controls the relay. I don't understand why it wants the relay to stay on but it does.
My battery would not drain overnight. The relay would draw ~2.5 amps. It took ~1 week to drain battery completely.
You should load test your battery first.
 

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Relays with time can start to stick. Most of the time, a simple tap on the relay will release the contacts. Relays are easy to replace, most are just plug-in. I would replace that relay before you even think about replace the ECU
 

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Discussion Starter #20
I'm trying to locate the ECM fuse. Should this be located in the engine compartment fuse box? I don't see one labled "ECM".
 
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