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  1. #1
    Join Date
    Mar 2019
    Location
    GA
    Posts
    35

    Default Why did my battery go flat ?

    '01 xc 70.

    After about 6 hours of sitting yesterday it was too flat to crank the car ( but did light up the dash etc ) and I have some really random thoughts, please tell me which ones are utter BS !

    Recently i replaced the blower motor resistor, with a cheap after market one. Since then I have twice walked outside and found the blower motor running. Googling suggests that this is a feature and shouldn't flatten the battery !

    I noticed that one of the back windows was not all the way up !

    When I go to start the car it says alarm system service required, I have been studiously ignoring this. Is it possible to simply pull a fuse and have no alarm ?

    I set the clock for the first time about two days previously, surely this is not relevant.

    I disconnected the + terminal overnight so that it would start this morning, when I reconnected there was a fairly good contact spark and a whirring noise from somewhere up front, I wasn't paying much attention. That indicated to me that something somewhat power hungry was on.

    Any ideas where to start with this.

    I am quite happy to "simplify" the car, if there are powered systems that aren't strictly necessary ( funny clicking from back wiper, headlight wipers making noises ) I have no issues unplugging stuff and taking out relays / fuses.

  2. #2

    Default

    I suppose the first question might be "How old is the battery"?
    Easiest first step might be to take the car to a car part store that can test for load etc and make sure its OK.

  3. #3
    Join Date
    Mar 2019
    Location
    GA
    Posts
    35

    Default

    Quote Originally Posted by AutosDirectFlorida View Post
    I suppose the first question might be "How old is the battery"?
    Easiest first step might be to take the car to a car part store that can test for load etc and make sure its OK.
    Should have mentioned, battery is only about three months old. The "dealer" put it in the day I bought the car.

  4. #4
    Join Date
    Mar 2019
    Location
    GA
    Posts
    35

    Default

    I will try that, although possibly in reverse order of your suggestions based on the least pain in the ass !

    Tks

  5. #5
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    584

    Default

    Quote Originally Posted by AKAMick View Post
    The Alarm module could have a bad battery, it will drain the car battery trying to charge it's dud battery up, unplug or replace the module internal battery, or the module itself if it is corroded to heck, or lastly just pull the alarm fuse.
    This was my situation with my 2002 resulting in drained battery. I pulled the fuse and I think I continued to get the message "ALARM SYSTEM SERVICE REQ'D" on startup. So I would clear the message and then be on my way. No more battery drain.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  6. #6
    Join Date
    Mar 2019
    Location
    GA
    Posts
    35

    Default

    Quote Originally Posted by Xfingers View Post
    This was my situation with my 2002 resulting in drained battery. I pulled the fuse and I think I continued to get the message "ALARM SYSTEM SERVICE REQ'D" on startup. So I would clear the message and then be on my way. No more battery drain.
    Awesome, everyone says these old euro cars are maintenance money pits, so far it's mostly a question of disconnecting superfluous and ridiculously over complicated systems.

  7. #7
    Join Date
    Aug 2017
    Location
    Pleasanton CA USA
    Posts
    486

    Default

    A large spark when connecting the battery indicates an abnormal load is draining the battery. It should be the tiniest spark (powering the clock, the door fob receiver, and the anti-theft module). Use the audible clue you already found....a stethoscope will help pin it down spatially ( faster than unplugging fuses). It sounds like a solenoid or motor stuck in the "on" position.

  8. #8
    Join Date
    Sep 2016
    Location
    Finger Lakes, NY
    Posts
    165

    Default

    If the dealer replaced the battery, check to see if the replacement was the correct spec. The one now in may simply be inadequate.

  9. #9
    Join Date
    Feb 2019
    Location
    Sourthern California
    Posts
    15

    Default

    I had a bad turn signal switch and we kept pulling the high beam fuse. Replacing the obviously damaged switch solved the problem.

  10. #10
    Join Date
    Mar 2019
    Location
    GA
    Posts
    35

    Default

    Update, thanks all, there is very good chance that the battery is the wrong spec, I was frankly stunned when they replaced the battery for free because the car wouldn't crank, I didn't expect that on a $3,500 car.

    So anyway I think I have solved it, but this car is real good at having minor issues which come and go at random. The fuse number 38 for the alarm was already blown and didn't change anything. I went into the wheel well and disconnected the siren. This seems to have fixed my issue.

    So having read some conflicting reports, I do think the alarm was the cause, I don't think that pulling the alarm fuse 38 will fix it in all cases, I think you have to actually unplug the siren unit. Having typed that on a day when my wife took the car, I bet it's flat at 5 pm !

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