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Battery draining itself Tommy Cooper stylee - dan
Dear all,
Called out the AA today. As most people assume, l thought l would never need them - how wrong l was.

Parked car, no problems whatsoever. Came back 6 hours later battery completely dead, like a bad episode of Star Trek involving power draining aliens. AA man was a gem, thought it may be the alternator as it wasn't providing as much current to the battery when the car was finally started as it should have (12.5v instead of 13/14v).

If wiring was at fault he suggested that the alternator could act to drain the battery whilst parked. Went to work after a 40 minute drive to get the battery charged up and parked it. Checked voltage/car start every couple of hours and didn't find a reoccurence, maybe the AA man had temporarily fixed it with his fiddling?

On opening car door later l noticed the brake lights had come on, and then went out of their open accord about 15 seconds after l locked it. Ambiguous Volvo saftey feature thought l. Came back to car 2 hours later, brake lights were on again and the battery was knackered. Jump start - quick drive, got out, brake lights on, keys not even in ignition.
Brake pedal appears to be bordering on triggering the brakelight even at rest, this would explain battery drain. Glad its not a more obscure electrical fault.

Anyone have an idea as to what l need to tighten/replace to stop this random car death problem, currently have bottle wedged under brake pedal when l'm not in the car?? (I'll try to remember its there before l attempt to drive away!)

thanks in advance,
dan
Re: Battery draining itself Tommy Cooper stylee - David Millar
Dan

You don't say which model Volvo which might help others familiar with the model. In principle, I would expect there to be a in-and-out switch operated by the brake pedal mechanism when it is operated. This would usually be operated by a simple mechanical linkage and somewhere just behind or above the brake pedal if you follow the linkage. When I fixed one on a SAAB 900 it involved lying flat on my back in the footwell and reaching up behind the dash.

At a guess, this switch may have worked loose on its mounting and therefore be touching the operational bit of the pedal linkage. If it is then I would expect your brake lights also to be on much of the time the car is being driven. It could be faulty, in the SAAB case the constant action of being used for 15 years or so had gummed up the sliding part with dust so a clean was all that was needed.

David
Re: Battery draining itself Tommy Cooper stylee - Andy P
I was always under the impression that the brake lights only operated when the ignition was switched on (at least this is the way they worked on all my previous cars).

It may be that the car has one of these new multiplex units which control the lights, in which case it may be that the unit is faulty.


Andy
Re: Battery draining itself Tommy Cooper stylee - Alwyn
Brake lights on Volvos and Mondeos will work without the ignition being switched on. Hence, if we come to a stop with our foot on the brake and turn off the engine, the lights are still on.
Re: Battery draining itself Tommy Cooper stylee - dan
Its a 480 (1991/2).
I was concerned about the light coming on during driving as well but short of being followed its tricky to ascertain.

Thanks for the comments, it was the fact that the lights came on when the keys weren't in the ignition that was bothering me..

dan