Ford Focus 2003 LX TDDI (90)

Battery light has been on for about 18 months, and ever since this first came on my heated front screen has been out of action.

When I start the car there is a short window of time (about 3-4 seconds) before the battery light comes on. Before this light comes on, the heated screen will work. The light on the button comes on, but once that battery light comes on, the heated screen turns off, as the light on the switch goes out.

My thinking is it cant be a fuse, because it wouldnt work at all, would it?

Any help appreciated

Rob

Battery light is telling car its not charging properly. All the while it thinks this it wont let the heated screens work as they are a huge battery drain

Fix the charging problem and I bet the screen will work again

battery charge light is something that should be investigated immediately and not left, problem could go from cheap to fix to expensive and leave you powerless in a dangerous situation. Suspect the bushes in the alternator have gone or wiring is damaged between alternator and battery

likely its either the battery is passed its best or the wrong type ie nota silver calcium battery or the alternator isnt charging properly a free battery test will show which it is

Cheers fellas.

I took it to my garage immediately, and the mechanic told me that the alternator was still charging the battery, and I would assume that that's correct, else the battery would have died by now.

How do I test for dodgy wiring then?

Do you have a voltmeter?

If so take a volt reading across the battery when the engine is off and its been sitting for an hour or so

Then take another reading when the engine is running

Tell us the results

Your on board computers think you have an issue for some reason, they don't just make it up

I know a man who has a voltmeter so I shall get on it! Watch this space. ..

Afternoon chaps...

Just been down the brother in laws who has a voltmeter

Cold charge on the battery is 12.03 and when the engine is running she is at 13.31/32

Thoughts?

12.03V is pretty low. Rule with our batteries at work is that if voltage drops below 12.50V then plate sulphation will take place, leading to irrepairable damage and lowering the capacity of the battery.

Also unless the battery has been left for 24hrs after engine running or had a load put on it with engine off, the voltage measured will be artificially high due to what's called 'surface charge'

So if your battery has still got some surface charge on it when you tested it and it's only just over 12V it'll be even lower when it's settled to steady voltage.

Only other thing to check is the voltage of the battery when disconnected from the car, in case there's something pulling the voltage down when you measure it.

Failing that, time for a new battery I'd say.

Thank you for your help!

Will topping up the battery (if needed) help?

Most batteries nowadays are 'Maintenance Free' which means the humble art of topping them up is now impossible. I would probably just stump up for a new one if I was you.

Sent from my Gen 1 WAP phone

It does have the cross head sections you can pull out.

Anybody any recommendations on a particular brand?

And are they as easy to fit as I would imagine?

Bosch silver is a good one cheaper from ebay delivered with engine running you want 13.9-14.4v so its not charging suggesting the battery may not be the right type or it has a faulty cell easy to fit just make sure you have the radio code

You wouldn't bother trying to top up then?

Wont make any difference the cells faulty its also likely its the wrong type of battery if not its passed its best by those readings

Does the fact the light has been on for 18 months not throw doubt on it being the battery?

Surely a dying battery would die within weeks of a fault. Have you ever heard of a duff battery going on for 18 months without a single (I mean not a SINGLE) issue other than the heated screen not functioning?

Could it be wiring??

Forgive my naivety but I gotta ask the questions as they pop into my head otherwise I will forever be wondering! All help is appreciated!

the fact is the figures you put up are not correct the correct figures are 12.5v when not running and when running 13.9-14.4 v is what it should be showing with the engine running so either the battery is faulty or the smart charge wiring is damaged or the alternator isnt doing the job using non ford garage for this is a waste of time mention smart charge the mechanic will give you a blank look diagnosis is required which isnt possible at home or come the winter you may find the car lets you down and yes ive seen faulty batteries and the incorrect type go for more than 18 months if its a lead acid battery the light would come on to say its not charging properly but it will get 12v from the alternator way below what it should so its not topping the battery up just keeping it at a static level however it will boil up and fail if the battery you have isnt a silver calcium battery simply check what battery is fitted thyat will tell you if its a silver calcium battery or not