2000 V40 Battery drains down when sitting

olddaddy · Post by **olddaddy** » 08 Jul 2015, 20:48

My wife teaches school and is off during the summer. The V40 sits quite a lot during the week and the battery drains down and it will not start without being charged. New battery, checked carefully for no lights on anywhere in the cabin etc. When the negative cable is removed I read 12 volts between the battery post and the cable and it sparks when reconnected. Pulled all fuses and found no arc or spark on re-installation. Car runs fine when charged and for a few days, but if it sits the battery comes up dead. Something is draining it. Any ideas?

olddaddy · Post by **olddaddy** » 09 Jul 2015, 10:41

I had the battery and the alternator tested this morning and they both appear to be fine, working as they should. The mystery continues........

difflock54 · Post by **difflock54** » 10 Jul 2015, 20:48

Did you include the front glove box when you were checking for lights staying on unintentionally?

Post by **alschnertz** » 11 Jul 2015, 04:33

850s are notorious for that glove box light staying on and draining the battery in a few days.

You can hook up a multimeter - set to display amperage - across the battery leads and then start pulling fuses until you see the display change. At least then you will know which circuit to focus on.

olddaddy · Post by **olddaddy** » 11 Jul 2015, 05:52

I did check the glove box to make sure it was off when closed. I checked for spark or arc when pulling and replacing the fuses, but by eye saw nothing. I will try the multi-meter.