Electric windows - is my battery on the way out?

[swigle]

Electrical and mechanical numpty here, so be gentle ...

Electric windows have stopped working when headlights are on. Ok when headlights off and other items drawing power (radio, heating etc). Ok when DLRs are on, it is just when I switch on the lights.

Safe to ignore given I know the circumstance under which they don't work, or should I get it checked out?

2012 140 SE, 52k on the clock, serviced by VW every 12 - 13k.

Thanks
Steve

 

[ArunAlec]

Does it happen with the engine running?

 

[owen_h]

It does sound like the battery could be on its way out. Do you have a way of measuring the battery voltage? Either using a multimeter or one of the plug in via the cig lighter socket ones. A fully charged battery should be 12.6V. Various 'state of charge' tables available on the web showing % by voltage. This one even adjusts for temperature:
http://www.meeknet.co.uk/e38/E38_Battery_SOC_Table.jpg

Measurements should be taken with engine off and ideally after being stopped for an hour or so. If you measure while the engine is running you will get around 14 volts which is what the alternator is charging at.
Garages can also do a load test on a battery which tests its ability to deliver power, they will no doubt then try and sell you a new one.

I have just had to replace the battery on mine (replacement delivered today, will fit it when there is some light). Also a 2012 140 but in my case a Beach. Noticed the dash cam was deactivating quite early and radio would only stay on a limited time (<10 mins) with engine off . When I measured the voltage it would only be 12.0 volts.
As an aside my brother has an Alfa Mito with the stop start technology, when his battery became low the stop start deactivated along with other more important features like the ESR (stability control).

 

[swigle]

Thanks for the replies.

Alec - happens with engine running, as well as with ignition on but engine not turning over.

Owen - will have a go with a multimeter tomorrow.

Cheers
Steve

 

[ArunAlec]

I would have thought that with the engine running that the alternator would give enough output to drive the lights and windows. Once you've done your multimeter check, I'd get it checked under load as Owen says. Good Luck! Let us know the outcome.

 

[Hotel California]

Thanks for the replies.

Alec - happens with engine running, as well as with ignition on but engine not turning over.

Owen - will have a go with a multimeter tomorrow.

Cheers
Steve

Think in that case it looks more like an electrical problem rather than a battery failure...

 

[owen_h]

Another thought that might be related is the top and bottom limits related to the 'one touch' window switch. If the battery has been disconnected these might need to be reset so that the system learns where fully up and fully down are. Procedure to reset should be in the handbook but I think its:
1) start with the window fully up
2) using the first 'down' position of the window switch roll the window down to the bottom and hold it there for 5 seconds.
3) using the first 'up' position of the window switch roll the window up to the top and hold it there for 5 seconds.

Worth giving the window and window channel a good clean as well in case the anti pinch feature is being triggered.

Given the symptoms you've described I'm not that convinced that it is the one touch but no harm in checking.
I also wouldn't discount there being battery issues even though they still occur with the engine running. My brothers Alfa remembered the state of the battery even after it had been started and the engine was running. The errors only cleared on his when a new battery was put in.

 

[swigle]

It's now looking like an intermittent fault - ok all today after 2 days of fault.
Multimeter test is delayed - friend has 2 so went round to test, to find that neither meter works.
'I don't understand - they worked the last time I used them.'
'When was that?'
'Oh, no more than 17 years ago ...'

 

[Californiaman]

Didn't someone have a similar problem some time ago and it turn out to be an electrical connection under the drivers seat that needed reseating...?

Sent from my HTC One using Tapatalk