[andrewdwhite]

Hi all,

My 06 Focus 2.0TDCI Titanium has just developed a fault and I wondered if anyone else has had the same problem.

The battery warning light has started to light up for periods whilst driving. This started yesterday, and have just checked the car this morning, it starts fine but now in addition to the battery warning light coming on, the front wndscreen de-icer won't switch on.

I've not had any other problems with the car and am away from home at the moment so would like to wait until I get home to use my usual garage!

Any help anyone can offer would be appreciated,
Andy

[MrDanno]

Sounds like a fault with the charging system or battery.

[andrewdwhite]

Thanks, was thinking it could be, but was a little confused as to why the front screen de-icer was not functioning too.

If the cause is a dodgy alternator will a long journey (350miles) cause damage to the battery?

My other thought was maybe there's a dodgy connection - Is there a common junction block connecting the warning lights and front screen switch?

[kings curate]

Could the warning light be on because there is a fault with the front de icer

[bby gti]

I'd check the charge rate really you want it to be 13.5 to just over 14volts . Battery warning light usually means it is not charging , means its charging below 12 volts, I wouldnt risk your 350 mile journey I doubt you would make it with the battery light on . When it doesnt charge it runs of the battery and it will go flat and your car will grind to a halt some where . Heated screens dont usually work if the alternator is not charging they need the extra power to work

[andrewdwhite]

Ok, thanks. Best get hold of a meter or send it in for a proper inspection then.

Thanks,
A

[jsoap]

Originally Posted by andrewdwhite

Ok, thanks. Best get hold of a meter or send it in for a proper inspection then.

Thanks,
A

I have the exact same problem, did you get to the bottom of it?
t

edit: I notice the battery light comes on, at the same time as the heated windscreen switch light goes off. My guess is that the ECU disconnects the heater, to save power, when it discovers that the alternator is not charging. Which appear to case since the battery is only reading 12V at idle. Strangely on the last run the light had come on and then went out again after 10mins.

edit2: light has now gone out and battery is charing at 13.9V. Must stop talking to myself.

[andrewdwhite]

Yes, after inspection at a dealer I've found out it's the alternator.

It's on it's way out, so is charging intermittently. The screen de-icer is indeed deactivated as it's a high current device so will drain the battery quickly.

Also noticed a kind of "wuring" noise when accelerating which apparently is syptomatic of alternator problems.

Been quoted £250 all inclusive to fit a new one. That's when they can get one - seems to be a bit of a shortage currently. Seems they may be prone to go after 50-60k miles from what I've heard.

Sorry for the bad news!

[MrDanno]

Have they checked it properly? This car has a smart charge system, So the procedure for testing involves measuring the signals with a scope.

Some Focus's also had a wiring loom problem with the smart charging system and a revised loom is available from Ford for about £20 or less but, I can't remember which years were affected now.

[jsoap]

Originally Posted by MrDanno

Have they checked it properly? This car has a smart charge system, So the procedure for testing involves measuring the signals with a scope.

Some Focus's also had a wiring loom problem with the smart charging system and a revised loom is available from Ford for about £20 or less but, I can't remember which years were affected now.

Interesting. In my case, when the light was on, I disconnected the 3 way smart charge connector on the altenator, and the battery voltage remained at 12v. So this would incdicate that the smart charge is not at fault (according to the inet pundits!).
Not sure about intermittent alternator faults, though sticking brushes could be possible. I'd plump for the loom issue. In the mean time I guess I should just cross my fingers.
Strange that no fault codes are coming up though!
t

[MrDanno]

Battery voltage with engine running and plug pulled on alternator should be 13.8 - 14.2 volts and should not drop when lights switched on.

There is a supply fuse for the alternator that can suffer with corroded terminals too. I think it is either f10 or f15 iirc.