what can drain the battery over night

Asked by Jun 07, 2015 at 09:32 AM about the 2004 BMW 5 Series 525i Sedan RWD

Question type: Maintenance & Repair

battery tested ok ,recharged it
what can i look for

2 Answers

113,825

The best way to find a draw is to put a test in between a battery post and the cable end, positive or negative it doesn't matter, if the lamp turns on you have a draw large enough to kill a battery overnight, then you have to start eliminating circuits, the first thing to do is electrically disconnect the alternator, if the lamp goes out you found your problem, if it doesn't then you need to start pulling fuses one at a time noting where each fuse went until the light goes out, when that happens find out what items are on that fuse and repair or replace the one causing the draw, then start putting it back together making sure the lamp stays off, finally reconnect the alternator. Now a note about parasitic loads, you might notice at first that the lamp will just glow slightly not a bright light, this is normal.

2 people found this helpful.

Thanks very helpful

Your Answer

BMW 5 Series Experts

  • #1
    Tom Demyan
    Reputation
    2,390
  • #2
    Michael Branan
    Reputation
    840
  • #3
    Robert Charlson
    Reputation
    700
View All

Related Models For Sale

Used BMW 3 Series
821 Great Deals out of 32,397 listings starting at $900
Used BMW 7 Series
117 Great Deals out of 4,791 listings starting at $3,950
Used Mercedes-Benz E-Class
412 Great Deals out of 20,095 listings starting at $1,500
Used BMW 6 Series
55 Great Deals out of 2,531 listings starting at $5,085
Used BMW X5
307 Great Deals out of 18,002 listings starting at $2,500
Used BMW M5
600 listings starting at $11,599
Used Mercedes-Benz C-Class
618 Great Deals out of 25,856 listings starting at $1,488
Used Audi A6
135 Great Deals out of 7,655 listings starting at $2,495
Used BMW M3
14 Great Deals out of 1,639 listings starting at $6,599
Used Mercedes-Benz S-Class
109 Great Deals out of 7,155 listings starting at $2,000
Used Honda Accord
429 Great Deals out of 101,582 listings starting at $1,200
Used Audi A4
195 Great Deals out of 12,599 listings starting at $1,800

Used Cars For Sale

2018 BMW 5 Series For Sale
38 Great Deals out of 5,329 listings starting at $45,849
2017 BMW 5 Series For Sale
16 Great Deals out of 344 listings starting at $40,450
2016 BMW 5 Series For Sale
10 Great Deals out of 439 listings starting at $20,991
2015 BMW 5 Series For Sale
114 Great Deals out of 2,921 listings starting at $16,991
2014 BMW 5 Series For Sale
64 Great Deals out of 1,130 listings starting at $14,700

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.