checking for a parasitic leak in your battery. DIY

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  1. checking for a parasitic leak in your battery. DIY 
    #1
    BMW Fanatic
    Car Details
    330diesel's Car Details
    Model of Car:
    330d SE
    Year of Manufacture:
    2002
    Transmission Type:
    steptronic
    Car Body Type:
    saloon
    330diesel's Avatar
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    May 2009
    Location
    essex
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    i recently had a leak that kept draining my battery after just a day. having struggled to find a novices guide on how to do it, i have put this up for fellow Beemer owners to use cos they will no doubt one day have this issue

    you will need a digital multimeter with a 10A or 20a facility. nothing flash i got one for £25 from Argos. they are on Ebay for £10.

    so heres how i did it: i cant take any responsibility for you deciding to following this. it worked for me and may do for you.

    1. connect the red wire to the 10A input of your multimeter
    2. connect the black wire to the 'com' input of your multimeter
    3. set the dial to measure Amps. preferably to the 10A setting.
    .................................................. ..........................

    4. disconnect the car batterys negative lead from the battery.
    5. connect the red wire of the multimeter to the negative battery terminal post.
    6. connect the black wire of the multimeter to the negative battery lead which you just disconnected.

    .................................................. ...........................

    your multimeter is now connected into your batterys circuit and is measuring all the current going thru it an hopefully showing the reading on the LCD display.

    .................................................. .............................

    to actually get an accurate reading of the cars battery whilst in sleep mode you have to:

    1. have the boot open to access the battery and multimeter and the boot light off
    2. find a way of stopping the interior alarm sensors from setting the alarm off whilst you check the fuses.
    3. ensure the interior light and glovebox light doesnt go off whilst you check the fuses.

    so to prep the car for the test you do the following:

    for the boot: either remove the boot light bulbs or push the latch on the boot lock to the locked position which switches the lights off.
    for the interior alarm sensor: cover the sensor by taping paper over it.
    for the glovebox light: tape the switch on the glovebox in the closed postition (small circular piece of black plastic on the front of the glovebox)
    for the interior light: open the passenger door and switch off the interior light using the button on the actual light.

    now leave the passenger door open and lock the car and set the alarm using the key buttons. go to the open boot and check to see what the mutimeter is reading. watch it for a minute or two and watch the reading steadily drop as the systems go into sleep mode one by one. once the reading settles after max 2 mins you can start.

    what you now do is go to the fuse box in the glovebox and disconnect one fuse and then return to the boot to see what the meter is reading. if the reading has dropped it means that the circuit that fuse is protecting is the faulty circuit (cos you have just disabled the whole faulty circuit that has the leak in it and the car is now working as it should hence the drop in reading) if the reading doesnt drop then replace the fuse in its slot and try this process with the next fuse and carry on till you find a drop and the faulty circuit.

    once the faulty circuit is identified you check to see what electronic items that fuse protects and work on them to fix the leak.

    .................................................. .............................

    to make life a lot simpler... get some crocodile clips and connect them to the metal points on the end of the multimeter wires. then connect these crocodile clips to the battery post and battery lead. this makes the whole process a lot easier as the connections are secure and fixed and you can then be free to go to the fuses under the glove box and back to the boot and the multimeter is always connected.

    my reading when the car was in sleep mode without any leaks was 0.005
     
     

  2. The Following 3 Users Say Thank You to 330diesel For This Useful Post:

    bobdisk (22-06-2013),Ferret (06-06-2010),xXxStKxXx (02-06-2010)

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  4.  
    #2
    Bimmer Fan
    Car Details
    xXxStKxXx's Car Details
    Model of Car:
    325i
    Year of Manufacture:
    1993
    Transmission Type:
    man
    Car Body Type:
    saloon

    Join Date
    Apr 2009
    Location
    North London
    Posts
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    Thanks for that Have moved it to the how to section and hopefully will help other members too
     
     


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