2002 Pontiac Grand Prix GTP, 3.8 supercharged...battery is being drained, charge it fully one day and cannot turn car over to start next day. Brand new battery which has been checked and is fine.
Asking for any help, suggestions. Something is draining battery overnight. We have checked cooling fan motors, suspecting might be alternator. Is there a way to test and what parts should we be testing? Any help would be greatly appreciated.
yeah take to technician and have a voltage test done. It may be a dirty ground or power wire coming from battery or alternator.
what if you have changed the battery and still getting the ?
do you have a sound system in the car?
with the key on, engine off, use a digital mutimeter with the leads in the fused ports on the meter to test amp draw across the main fuse. may be labeled as the solenoid fuse. positive lead on the battery side, negative lead on the electrical system side. write down the result, then put the fuse back in and turn test the amperage output of your charging system at the wire leading from your rectifier (the box that your alternator runs to) with the negative lead to ground. if the result of your charging test is lower than your draw test, there may either be an issue with your alternator, your voltage regulator, or possibly you may just have too many accessories running at one time. i had this issue, and ended up buying a high output alternator to pick up the draw that my audio system was creating. if there is no issue with the charging system, you likely have an unwanted ground somewhere in your electrical system.
Well Bernard has the tech solution there. If you cannot locate the problem and don't want to spend a small fortune on diagnostics, you might try installing a battery cutoff switch. These are inexpensive and can be mounted on the outside so you don't even have to open the hood to turn it on.
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