Alarm sounding when battery is dead - help!
Thread Starter
Newbie
Joined: Mar 2014
Posts: 3
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C270 CDI
Alarm sounding when battery is dead - help!
Hi folks, am new here.
Recently bought a C270 CDI 2001 - drives like a dream but in the last week had this issue:
Usually I leave my MB in the garage after work around 6pm. For weeks it has been fine but as of late, from 11pm to 4am, the alarm starts screaming for 10 minutes or so then stops. Although the alarm wakes the entire neighbourhood I cant turn the alarm off because, you guessed it, the battery is totally dead and the remote fob wont work.
So I jump start it the next day, went for a long drive.....after work I parked up at 6pm or so, made sure nothing was left on. Same thing again - alarm screaming at 2am....
I've been told that I have a parasitic drain of some type - its not the electric memory seats because a cut-off switch has already been applied to these to prevent them from causing drain. I keep that switched off unless I am adjusting the seats.
I'll take it to an indie dealer this week to get looked at, I know they check draw on all the fuse circuits to detect where the short might be occurring and go from there. My question is this:
Why is the alarm sounding and does this give any clues as to where the drain is? Is this perhaps a security feature to warn the owner that there is insufficient battery power left to keep the alarm working? I cant see anything in any forums about this. Is there ANY way I can disengage this feature? I've tried taking out the alarm fuse but of course then the whole locking system wont work and I cant even lock the car with the fob. Please help as I am sure my neighbours will kill me if it happens again tonight!!!
THANKS
Dave
Recently bought a C270 CDI 2001 - drives like a dream but in the last week had this issue:
Usually I leave my MB in the garage after work around 6pm. For weeks it has been fine but as of late, from 11pm to 4am, the alarm starts screaming for 10 minutes or so then stops. Although the alarm wakes the entire neighbourhood I cant turn the alarm off because, you guessed it, the battery is totally dead and the remote fob wont work.
So I jump start it the next day, went for a long drive.....after work I parked up at 6pm or so, made sure nothing was left on. Same thing again - alarm screaming at 2am....
I've been told that I have a parasitic drain of some type - its not the electric memory seats because a cut-off switch has already been applied to these to prevent them from causing drain. I keep that switched off unless I am adjusting the seats.
I'll take it to an indie dealer this week to get looked at, I know they check draw on all the fuse circuits to detect where the short might be occurring and go from there. My question is this:
Why is the alarm sounding and does this give any clues as to where the drain is? Is this perhaps a security feature to warn the owner that there is insufficient battery power left to keep the alarm working? I cant see anything in any forums about this. Is there ANY way I can disengage this feature? I've tried taking out the alarm fuse but of course then the whole locking system wont work and I cant even lock the car with the fob. Please help as I am sure my neighbours will kill me if it happens again tonight!!!
THANKS
Dave
Member
Joined: Jul 2010
Posts: 85
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c230k
What you'll need to do is get a multimeter and start checking fuses with the car off to see what's draining it.
To stop the alarm temporarily just use the mechanical key to lock the driver door when you get out. I know it's a hassle to do that instead of the electronic locks, but as long as the security system isn't engaged the alarm shouldn't go off when the voltage drops.
Hope this helps,
Tim
To stop the alarm temporarily just use the mechanical key to lock the driver door when you get out. I know it's a hassle to do that instead of the electronic locks, but as long as the security system isn't engaged the alarm shouldn't go off when the voltage drops.
Hope this helps,
Tim
Thread Starter
Newbie
Joined: Mar 2014
Posts: 3
Likes: 0
C270 CDI
Hi Tim - thanks for this. It seemed to do the trick.
So this is a known feature, alarm triggering when the battery strength gets low? Seems like a useless feature if it sounds when the battery is SO LOW you cant even disengage the alarm or turn the key!
Dave
So this is a known feature, alarm triggering when the battery strength gets low? Seems like a useless feature if it sounds when the battery is SO LOW you cant even disengage the alarm or turn the key!
Dave
