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Thread: Battery discharging when left
02-13-2009 08:53 PM #1
Battery discharging when left
So the car sat for 3 weeks and it started right up. Then, the next day, the battery was dead. It will stay charged for a couple hours at least but when left over night it goes dead.
does anyone know what the amp draw of the car is supposed to be when off? should i just measure the amp draw then start pulling fuses?
02-14-2009 05:31 AM #2
finding a shoert - for beginners
Either your battery is almost dead, or you have a drain. Ask a shop to test the battery under load.
If you are a beginner in electric issues, this walks you through it, hopefully:
I'll try to make it simple, ...
The meter should have an A scale (Ampere) for reading current. Preferably, a High amp one (10A for example). In some of them, this high amp scale requires the red plug of the wire probes to be connected in a different hole. We do not know the magnitude of the current involved, so in order to preserve the meter, it is better to start reading in this high amp scale.
Disconnect the ground (negative) lead to the battery (electronic devices in the car will loose status when battery is unplugged, so you will need radio code for example), connect the positive (Red) meter probe to the negative thick wire to the battery, and connect the negative (Black) probe of the meter to the negative battery post. Be sure that the probes are inserted in the proper holes in the meter for the readings (Amp) you intend to take.
If you have a leak as you assumed before, you should have a significant reading in the meter (maybe/sometimes more than 50 milli amps, > 0.05 Amp). If the selected scale do not allow you to have a clear reading of the leaking current and you want to change down scales, do so. Remember that some meters require to select a new hole in the meter for the red probe in order to select a lower Amp (Current) scale.
Once your meter is properly set and you have a good steady reading of the leaking current, proceed to remove, one by one, the fuses on the fuse box. Keep an eye to the meter in order to identify which fuse removal is dropping down the current in the meter. The leaky circuit is feed by that fuse.
Investigate what devices are associated to that fuse, plug the fuse back, and start disconnecting all devices one by one until you get again a reading drop. That device would be the culprit.
But in case of our E32 the complete electronics come to a rest/sleep modus after about 16 minutes. That means that you should not open the door again for example but keep it locked for checking. Therefore open the rear windows and the hood, remove rear seat and then lock the doors and wait 16 minutes. Then you have access to the battery and the fuses thru the rear windows.
If the door is unlocked, the GM is again on stand-by modus and maybe others.
When all is 'sleeping' usual drain is 30-50 mA.
The wiring diagram for E32 cars are here:
Download this one.
It has fuse charts, power distribution, ground cable distribution etc.
Best is you study these almost 700 pages and print out the most important ones for this task.
When you have identified the fuse(s) in question and need more help, please let us know in detail what you have done, what disconnected etc., details are very important. There are people here on the board which can guide you thru it.
Shogun E32 Tech Tips: http://twrite.org/shogunnew/topmenu.html
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