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Being cheeky with a 45 question but might be relevant to a 7 by PaulT


PaulT
A facelift 45 1.8 auto that keeps discharging its battery when left standing. I have read that the alternator can cause this. I disconnected the plug but left the actual ‘power’ cable attached (it looked as though the alternator would need removing to disconnect this. Should I have disconnected this cable and any other thoughts if it is not the alternator.

Thanks in advance
Paul

That apart Mrs Lincoln, did you enjoy the play

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Posted 10 Jan 2012, 06:48 #1 

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Duncan
If it is the alternator, it could be a failed diode and the main power cable could then cause a discharge. Saying that, I've not heard of an alternator doing this without giving other obvious symptoms.

You really need to get a meter on it and start removing fuses until the drain drops off.
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Posted 10 Jan 2012, 07:55 #2 


PaulT
Did try with a meter from the cable to battery but the alarm went off!

Will find the sounder, disconnect it and then use the meter and start pulling fuses...now thinking about it I could use the resistance option and not involve the battery just find which fuse when pulled increases the resistance.
Paul

That apart Mrs Lincoln, did you enjoy the play

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Posted 10 Jan 2012, 08:30 #3 

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Duncan
The resistance will be too low to get a helpful reading I'm afraid.

For the alarm to go off, you must have set it by locking the car I would expect. Should be no need to do this as the drain will probably be there with the car asleep too.
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Posted 10 Jan 2012, 13:26 #4 


mh007
I had the same problem with my Renault Trafic Van.
Checked just about everything with a meter & no other symptoms, no voltage drop & Alternator charging fine.
I happened to be by the front of the van very early the other morning & heard a feint 'buzzing' sound from the front of the van.
After further investigation, I removed the Battery + cable from the Alternator & the noise stopped.
Fitted a new Alternator & now all is fine.

Posted 13 Jan 2012, 21:04 #5 


yl51hfb
The sounder is either under the coolant tank or the windscreen scuttle. I wouldnt rule out the alarm system on the later cars. Its not upto much and is well known to give trouble.

Posted 10 Feb 2012, 22:26 #6 

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