New battery in a e39 and it still dies overnight.
Discussion
I've just had the original battery replaced with a new one as it would die through out the cold night and not start that car in the morning. The car is driven for a good hour in the morning and 1.5 hours in the evening so i would have thought that it would get a good charge, but yesterday morning the car wouldn't start again because of a flat battery (even though this one is new!)
One idea was that the alternator was on it's way out, but i've had this checked by a sparky and there is a crrect flow. So the only other thing i can think of is something to do with the cabin fan.
When driving i normally have the heater on to keep me warm, once i've gotten to work/home and i've turned the car off and removed the key i can hear a fan still turning. It's not the engine bay fan as i've checked this and it's not spinning, but it does sound like the cabin fan/heater still running.
Is this possible and could it be the cause of my battery running flat?
thanks
DJ
One idea was that the alternator was on it's way out, but i've had this checked by a sparky and there is a crrect flow. So the only other thing i can think of is something to do with the cabin fan.
When driving i normally have the heater on to keep me warm, once i've gotten to work/home and i've turned the car off and removed the key i can hear a fan still turning. It's not the engine bay fan as i've checked this and it's not spinning, but it does sound like the cabin fan/heater still running.
Is this possible and could it be the cause of my battery running flat?
thanks
DJ
Yes. I'm surprised the auto sparks didn't pick up on it. You need to get an ammeter in series and measure the current draw with everything off. It should be neglible. Can you pull a couple of fuses to stop the fan while measuring the draw?
If you can't get an ammeter just pull the appropriate fuse and stop the fan. If the problem goes away you've found the fault
Probably a duff switch.
If you can't get an ammeter just pull the appropriate fuse and stop the fan. If the problem goes away you've found the fault
Probably a duff switch.
Remove the fuse that provides the heater fan with its power, leave overnight and see what happens.
Or turn the car off and disconnect the positive on the battery and connect a multimeter on DC amps scale between the positive battery terminal and positive power lead to check the current draw.
Do you have heated door locks? They went funny on my M3 and stayed on all the time, battery flat in no time.
Too sloooooooooow.
Or turn the car off and disconnect the positive on the battery and connect a multimeter on DC amps scale between the positive battery terminal and positive power lead to check the current draw.
Do you have heated door locks? They went funny on my M3 and stayed on all the time, battery flat in no time.
Too sloooooooooow.
Edited by r5gttgaz on Wednesday 24th January 09:22
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