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Discussion Starter · #1 ·
Have a Giant Mystery with our 99 Se
Battery suddenly going bad after replacing only 6-7 months ago....Brand New battery Draining within hours. Belt is also relatively new and seems to check fine. Have already had both batteries and alternator checked, they check fine. Grounds and connections appear to be tight and clean. Dome light staying on, I have it disconned for the time being, door adjar light on, and wipers suddenly working intermittently, mostly when using turn signals. The check battery light came on momentarily two fridays ago, but only long enought to get my attention. Couldn't have been on for long as the total trip lasted only about five miles. Ran fine for a few days then whammo all of these wierd problems started occuring.
What the heck, I really need to get my car going for work, my job site is 60 miles round trip and my truck is really eating our lunch right now!
Any help would be greatly appreciated as this seems to be a real problem with the gen 3's as I have read 170 similar articles before being referred here...All with the very same situation lights and all.
Thanks.
 

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So, have you checked any of the wiring harnesses for chafing/exposed wires? I would trace all harnesses into the fire wall, re-check all grounds, and get a second opinion on the vehicle electronics scan.

Some places have a parasitic drain part of the test that would tell you if you have anything that is draining your battery when the car is not running. I would also get the voltage regulator checked since weird voltages lead to weird problems with your car's computer and electronics. (speedometer and tachometer went wacky when my wife's alternator went out)

Also, you might need to replace your battery leads if they are heavily corroded on the inside. (white/gray stuff between all of the smaller wires) This would lead to high resistance and insufficient charging from the alternator perhaps.

Hope this helps!
 

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I solved the problem on one Taurus by converting to side post. Changed the cables and battery at the same time, never had a problem again. I think sometimes the hood insulation touches the battery and causes this problem, in theory.
 

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Discussion Starter · #5 ·
Have checked the obvious...Checked on two different computers for the second opinion. I will make another attempt at finding a grounding problem in the wires, although, this was the first, second, third, etc. we looked for. I have a technical background, although somewhat limited when it comes to computer mods and things.
I was referred to this website from another where as I had stated before, there were 170 extremely similar posts, down to the exact lights.....Hoping that someone here has the cure for this since as of the other day, on the other site, there were several of us having the same trouble with no result. I cannot afford another dealership, shop, and hundreds of dollars attempting to solve this on our older car...The wife is nearly ready to give it up, and considering replacement...I just hate to give it up if there is some hope of keeping the car going affordably.
Thanks to all.
Craig
 

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Dome light staying on is a common problem, make sure you address that first, it's an easy fix if you do it correctly.
If you hook up a meter that can read current flow in amps, you can find the phantom drain problem, if that's what it is. Disconnect your battery ground cable and put one meter lead to the ground cable and the other lead to the battery ground post. With the ignition off, you will read current flow on the meter. Then, one by one, pull fuses until the meter drops to zero. If it does not drop to zero on a particular fuse, put it back in and move on to the next one. This will tell you what part/system in your car is draining your battery when you get to the fuse that makes the meter drop. Make sure to check every fuse, if you get a partial drop in current on one fuse, but not a drop to zero, there is more than one problem, leave that fuse out and continue on until your meter reads zero current flow. Good Luck!
 

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I addition to what Dan said, a bad diode in the alternator can cause a significant drain on the batt. While measuring the current drain as Dan said, disconnect the output wire from the alternator and see if the drain goes away. Easiset way to do this is at the megafuse. I have been bit by the bad diode problem once or twice in the past.
 
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