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Date: Wed, 19 Mar 2003 16:59:03 -0000
From: "GG" <>
Subject: Re: 1989 has battery drain

"John Davies" <> wrote in message news:b7pc7vobecrevqadvibfj8kod8d2jc7kennopsamcom... > On 17 Mar 2003 15:01:45 -0800, (Amy > Young-Leith) wrote: > > >I few weeks ago I bought a 1989 900 (non-turbo). It's a POS with over > >225k, but looks great and is fun to drive. I paid diddly for it so I > >figured if I had to tinker with it... well, it would be a challenge. > > > >I seem to have a power short somewhere. The battery will be DEAD, and > >it'll jump start just fine, and charge the battery up enough to start > >again if you shut it off. But overnight, it drains back down to zilch. > > > >This happened once when I first got it... then didn't happen for a > >while, and now is happening all the time. > > > >My first thought is to replace the battery, but a few people have said > >that since it'll charge back up, they don't think that's it. It had a > >new alternator on it about a year ago. > > > >The answer may be that I have to take it into a professional, but > >that'll have to wait a while. Anything a handy but car-dumb person can > >do to self diagnose? > > > >Amy > > > First of all, the battery is probably junk. Locate an automotive > battery charger, charge the battery at least overnight, then drive the > car to a local shop and have them test the charging system and the > battery. Usually they will do this for free in the hopes of selling > you some new parts. You have no obligation to buy from them. They need > to do a load test to see if the battery has adequate capacity, and > they need to check the alternator to see if it is charging fully at > idle. Either problem MUST be corrected before proceeding. > > It's pretty easy to determine if there is an abnormal drain - the > problem is finding what exactly is causing the problem. The best way > for you to at least isolate the cause is to buy an inexpensive digital > voltmeter at an auto parts store. Get one that has an ammeter function > of at least 1 amp. 10 amps would be better (and more costly). > > Charge the battery and remove the negative (black) battery cable. Set > the meter selector dial to amps (current reading) and connect the > black meter wire to the disconnected battery cable, and touch the red > meter wire to the negative post on the battery. With this > configuration the meter will show how much current is flowing through > the battery. > > With the ignition key OFF, there should be no more than 0.1 or 0.2 > amps. Any more than that and you have a serious drain. You can start > pulling fuses one at a time, and replacing them, until the abnormal > drain goes away, and that will tell you the circuit that has the > problem. > > In addition to a meter, you really need a good electrical diagram. > Once you figure out which circuit is bad, you can check out the > components on that circuit and hopefully locate the culprit. > > Good luck - this sort of electrical problem can be frustrating to > solve. Don't hesitate to ask again in this group, or ask a friend with > electrical knowledge to help you. > > My suspicion is that if you replace the battery everything will be > fine. > > John Davies > Monroe WA USA > > 2001 Saab 9-5 Aero Wagon > 2000 Audi A4 quattro 1.8T > 1991 Jeep Cherokee Laredo 4x4 > May be a long shot but mine was simply the glove box door not shutting properly and hence the glove box light not going out - it didn't happen all the time and drained over night! GG

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