coolamasta

Grrrrr right I bought a Focus TDDi a few months ago as my run about for work (go to London a lot) and 2 weeks ago coming back from London in torrential rain I had on, dipped lights, fog lights, wipers on full, heaters on full blast, rear heated screen on and stereo loud to drone out other noises lol

Anyway battery light came on all of a sudden and everything dimmed and got slower lol, quickly switched everything off and light went out and dash got brighter again, soon as I turned any of it back on, IE rear windscreen or heaters then the light would come on again so put it down to dying alternator so managed to get home (just) on battery power, literally watched dash lights get dimmer and wipers get slower lol...

Anyway it was a bastard of a job but I fitted a new alternator and charged the battery up but now when I start up batt light goes out but comes on again afer 45 seconds-ish, im getting 12.6 volts from the battery when engine is off and 14.4ish when idling so new alternator is charging it...

Anyone got any ideas why it keeps coming back on? I have been driving it for last week with everything running without any dimming etc but then ive heard these have an intelligent charging system which is controlled by a pcm which could be playing up, any gen on this?

Thanks for any help...

coolamasta

Bump

iansoutham

The regulator on the Focus is not internal to the alternator, and the dash illumination is controlled by the engine ECU. The Focus has what is called a "smart-charge" system where it only supplies the amount of juice needed, providing more power for the engine by not sapping it all with an alternator.

TBH, I would get it checked professionally, as when I worked for Fords, we were always getting Focus' in (mainly ST170 versions) and they could be anything from alternator, to ECU to main engine loom wiring.

coolamasta

Cheers bud, I would rather try and get it sorted myself as its only a runabout and dont wish to pay ford silly money...

I have checked all wiring and everything seems fine, another question though, would a dying battery make the light go on? The dash lights seems to fade more than they used to while cranking before the other alternator died...

iansoutham

Hard to say TBH, it is technically possible, but I have never experienced it myself. Exhange usage of another battery as a temp. measure for experimentation would be the only way to answer that.

MATT222

where have you checked the wiring??
has the blue wire on the mutiplug got 12v??
this wire usally snaps causing the light to come on
also is the alt shaft spinning the alt???
there is a fuse that blows in the engine bay fuse box
if not pm me and i'll talk you though

coolamasta

Ahh thanks mate, have just checked the fuses again and there doesn't seem to be any blown, I will have to remove the intercooler to check that the blue wire has +12v?

The wiring looks sound, the cars only done 70k so the wires look almost perfect, I have unplugged the multiplug, sprayed contact cleaner in the terminals and put it back together again, the alternator is charging the battery as im getting 14.4v when idling, its just the light comes on after its been running for about 30-45 seconds..


UPDATE: One thing i noticed last night, when i started it up I put headlights on but the dash and headlights got brighter as I revved it but soon as the battery light comes on they get brighter and stay brighter, im just wondering if it could actually be anything to do with the battery?!

coolamasta

BUMP, fookin light still comes on, done another 500 odd miles and the batt is charging fine, also have not driven it in a week as been using the evo but it still started and ran fine today, just annoying the crap out of me that the light is on Grrrrrrrrr

coolamasta

BTTT again, need to get this sorted, does anyone know where the charging ecu is?

B19 JUB

its the main engine ecu that controllers the light as ian says with the smart charge system.its prob logged a generator fault in its memory.best to get to fords to double check that and to erase the codes.