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1994 BMW 540i Question: Brand new battery dies if left for 24 hours. What could be draining the battery?

 

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540guy, Sherman Oaks, CA, July 30, 2013, 21:04
 Rookie

Having some weird electrical problems. The back up lights are not working. The interior panel lights (speedo) dim sometimes. The trip computer went into 24hr mode and then back.

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  • Answer #1

    Avery Automotive from Avery Automotive Repair and Towing, July 31, 2013, 05:33
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     Technician

    I would start by checked all the doors and trunk to make sure lights are off. Might have a big short somewhere making battery draw. Would take to a repair shop and they can install a meter to battery and start removing fuses to see what is making draw

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    540guy, August 01, 2013, 21:14
     Rookie

    It turned out to be something that took a master BMW mechanic 2 days to find. After pulling the primary fuse box and the secondary fuse box and going thru all the relays there was still a big draw. It seems that even though it was still functional one of the seat motors was in the constant "on" position. We have a combined 50 years of experience working on BMWs and neither of us had ever seen that. Replace the seat motor and problem solved.

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  • Answer #2

    Greg's Orange Auto (13401 Answers) , Orange, CA - (714) 361-9386
    globalhelper July 31, 2013, 06:34
     Master

    you have a constant pwr draw, have it ck'd out

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    540guy, August 01, 2013, 21:15
     Rookie

    Turned out to be (after 20 hours of work) a shorted out seat motor. It worked but was alway in the "on" position. Thanks for your input.

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