2001 S80 T6 - battery dead (again) when car is turned off

lghyams · Post by **lghyams** » 09 Sep 2009, 15:34

I have a 2001 S80 T6, and about two months ago, it was dead after being parked for about a week. Although the battery was only 9 months old, I replaced it (per Pep Boys, the only place within close proximity to me), and life seemed good.

Fast forward to today - and again, the car was parked for about 9 days, and went to start it up - same thing. Not even a click-click-click - dead as a door nail.

No warning lights have come on to tell me that this is an alternator issue - and when the battery was replaced 2 mos ago, Pep Boys supposedly did a charge test and said everything was fine.

Any thoughts on what could be causing this? Is this typical of an alternator issue - or something else electrical. Just want to have as much info as possible before I go to a car mechanic.

Thanks for your insight
Lisa
Atlanta GA
2001 S80 T6
87,000 miles

Post by **vegasjetskier** » 09 Sep 2009, 16:14

Make sure the light switch is not in the parking lights position - that will leave the lights on all the time. Also check that the glove box door isn't warped - that could leave the glove box light on all the time.

lghyams · Post by **lghyams** » 09 Sep 2009, 16:26

Actually, I was thinking it was the a/c fan being left on. It was coming on mysteriously even though the car was off for a while there, but my daughter insists she turned it off (she was last one to use it, and knob was in off position today).

Just seems weird that this is the second battery issue in such a close period of time. Doesn't the alternator warn you if it's going bad? Or could this be a short somewhere (dreading that) that is draining my batteries???

Post by **vegasjetskier** » 09 Sep 2009, 17:33

The car turns on the AC fan automatically to remove moisture from the evaporator so it doesn't corrode.

My car will last about 3 weeks sitting untouched before the battery goes dead. This is due to all the computers in the car that create a draw on the battery. Perhaps the battery that Pep Boys sold you doesn't have the capacity of the original.

lghyams · Post by **lghyams** » 09 Sep 2009, 18:47

Could it be the alarm system draining the battery? A while back, I was told that the alarm system needed servicing, so just wondering if that could be it? The battery is only 2mos old and is the correct battery. Weird that the previous battery was only 9 mos old and needed replacement too...I'm thinking the cell on that one went bad but two in a row???

Post by **vegasjetskier** » 09 Sep 2009, 19:34

The batteries on the alarm sirens go bad after a few years. The electrolyte leaks out and eats up the computer circuit board. I suppose this could create a short and drain the main car battery.

Here is a link on how I changed my siren when it went bad. You can see the computer board damage in some of the pics.
https://www.matthewsvolvosite.com/forums ... 11&t=17479

lghyams · Post by **lghyams** » 10 Sep 2009, 10:10

Thanks for the info.

Took it to the shop today, and they believe that a faulty door lock is causing the siren to alarm, which is draining the battery. The siren chip is also bad - which is why we haven't heard a siren!

They wanted $800 to fix the door and the chip. Told them just to fix the door and will try to get the chip done myself.

Thanks for your help!
Lisa

DrDootz · Post by **DrDootz** » 10 Sep 2009, 11:27

It could be the start of an alternator issue. You can do a basic alternator check with a voltmeter. If you don't have one you can get one at Harbor Freight for around $5. The battery is in the trunk but there is a battery "port" under the hood towards the back on the driver side under a red plastic piece. With the car off it should measure about 12-12.6 volts. Start the car. It should measure around 13.6 and above. Turn on a/c,lights,radio and rev to about 2000rpm. It should stay in the mid 13v range. If it doesn't pass this simple test, you may have an alternator issue.

Good Luck - DrDootz