Bad batteries or current draw?

[samer0214]

Originally Posted by 80stech

Checking current draw isn't quite so easy because you need to supply power to everything until sleep comes in and then have the ammeter or shunt in place without disrupting the circuit. Best way is with some kind of battery switch. It's not hard but you have to keep those things in mind.

I understand the ammeter in series between the battery post and the battery terminal, but not sure I understand the role of the shunt in the setup. Can you please explain?


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[samer0214]

Originally Posted by Zulu95

Do you have any aftermarket ipod or whatever charger wired in the vehicle. A lot of people have found these to be the source of "no sleep mode" problems.

Bone stock, no accessories added.


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[Fifty150hs]

Originally Posted by samer0214

Bone stock, no accessories added.


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Do you have bluetooth?

[samer0214]

Originally Posted by Fifty150hs

Start with radio, NAV and telematic (blue tooth module). Pull fuses for all of them and start putting them back in one at a time. When you insert one that results in a dead battery, you have your culprit. Had a similar problem after alternator took a dump. New alternator and new battery and it kept dying over night. Parasitic drain turned out to be the telematic that wasn't "going to sleep" like it was supposed to. Removed the telematic and problem solved. Best of luck!

Just to be clear, this diagnostic should start after the truck has gone into sleep mode, at which NONE of the modules should be "alive" after 16 minutes?

On a perhaps related note, when the headlight switch is in the automatic mode (leftmost position), the lights are always ON regardless of ambient light level, they do not turn toggle, as if the light sensor/module is stuck in the always ON mode. Lights do go off when the car is shutoff. Related? Is there a separate sensing module for that function? Could it be the culprit?


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[Fifty150hs]

Originally Posted by samer0214

Just to be clear, this diagnostic should start after the truck has gone into sleep mode, at which NONE of the modules should be "alive" after 16 minutes?

On a perhaps related note, when the headlight switch is in the automatic mode (leftmost position), the lights are always ON regardless of ambient light level, they do not turn toggle, as if the light sensor/module is stuck in the always ON mode. Lights do go off when the car is shutoff. Related? Is there a separate sensing module for that function? Could it be the culprit?


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The sensor for the automatic headlights and automatic wipers is on the window by the rear view mirror. It's concealed by the black cover behind the mirror. Have you or the previous owner changed the windshield using non-BMW glass? When I changed mine it stopped working. You may also have a bad module. If you take the cover off you can unplug the sensor and see what happens. The cover is shown as number 6 here: RealOEM.com - Online BMW Parts Catalog