Faint Battery Light Coming On

[craig79]

As above, the battery light is staying on whilst running.

I've tried the basics eg. tightening fan belt & charged the battery.

I put a multimeter across the battery when off and was giving a good

12v reading (bearing in mind I'd just charged it the day before). Tried again

when running and again a healthy 13 ~ 14v across the battery. Just picked

up a battery there in order to wittle down the possibilties, haven't fitted it yet,

anyone got ant suggestions if the little b.ugger stays on ?? Thanks everyone,

Craig.

[little vodka goblin]

As above, the battery light is staying on whilst running.

I've tried the basics eg. tightening fan belt & charged the battery.

I put a multimeter across the battery when off and was giving a good

12v reading (bearing in mind I'd just charged it the day before). Tried again

when running and again a healthy 13 ~ 14v across the battery. Just picked

up a battery there in order to wittle down the possibilties, haven't fitted it yet,

anyone got ant suggestions if the little b.ugger stays on ?? Thanks everyone,

Craig.

Had this problem when I had an Escort (many moons ago) and it turned out to be a dodgy alternator - hope this helps

Edited October 15, 2007 by little green goblin

[craig79]

Had this problem when I had an Escort (many moons ago) and it turned out to be a dodgy alternator - hope this helps

Cheers mate, that was my first impression but seeing the increase in voltage

across the battery when ticking over made me think again

Craig.

[scoobykev]

Bad earthing??

[craig79]

Bad earthing??

Could be Kev, gonna give the terminals a wee clean when I

go to put the new battery on.

Craig.

[scoobykev]

Could be Kev, gonna give the terminals a wee clean when I

go to put the new battery on.

Craig.

check the earth strap from the engine to the body of the car, that went on one of my old fords and gave me loads of grief.

[ed-209]

When running at about 2000rpm the alternator on a ford should give out 13.2v-14v

If the light is very faint (like you can just see it in daylight) It could be the recifier/regulator pack on the alternator

if its brighter than that it could be bearing on it cause by the fan belt (alternator belt) being too tight

If you hear a screaching noise when reving the fan belt (alternator belt) is loose.

What age is the fiesta. The alternator don't last forever.

If it was me I would put a multimeter on the battery should be 12-12.6v start the engine should drop to 9-10v

then pickup again with the engine speed rev the engine to approx 2000rpm voltage should go up and stablize at 13.2-14v

then while still reving at 2000rpm switch on high load items, heater, demister, full beams voltage should drop and then go back to 13.2-14v

that shows that the recifier/regulator is working. if it goes down and stays down then time for a new alternator

hope that helps a little.

Ed.

[euan_r]

worth checking voltage output higher up the revs as well if you suspect alternator shouldnt go over about 14v. be worth checking the main charge lines as well as had something similar with brothers focus and turned out to be earth strap.

[superstar_tradesman]

I've had many a feesty over the years and come accross this several times, it's the rectifier in the alternator.

Best bet is going to an auto electricians and getting a recon alternator, some'll even do an exchange on your faulty one.

[craig79]

Cheers lads for the info. Got the new battery on last night,

after sanding all the connectors i could get off (some bolt heads were like

blobs of rust - good auld fordies ).

B.loody light was still on, getting low 12's over the battery when car was off,

high 13's / low 14's when revving at 2k with dimister etc off, low 12's when

idling with everything switched on and high 13's / low 14's with everything on

and revving at 2k ?????

Mystery, so I handed it back to her explaining just to keep an eye on

the turn over speed, when it shows signs of slowing up I'll go and get another

altenator. Get's a phone this morning; "the light's went off", god knows - as i

said 'good auld fordies' !! Thanks abody for your wee tupence worth

Craig

[billyboy]

Cheers lads for the info. Got the new battery on last night,

after sanding all the connectors i could get off (some bolt heads were like

blobs of rust - good auld fordies ).

B.loody light was still on, getting low 12's over the battery when car was off,

high 13's / low 14's when revving at 2k with dimister etc off, low 12's when

idling with everything switched on and high 13's / low 14's with everything on

and revving at 2k ?????

Mystery, so I handed it back to her explaining just to keep an eye on

the turn over speed, when it shows signs of slowing up I'll go and get another

altenator. Get's a phone this morning; "the light's went off", god knows - as i

said 'good auld fordies' !! Thanks abody for your wee tupence worth

Craig

There is a multi-plug which runs under the radiator which is the wiring from alternator to battery.Very bad for corroding and make and break contacts as well.Check it oot and see if your car is wired this way.If so get rid of the multi-plug and replace with terminals.Also chaffs against body work here too.

[craig79]

There is a multi-plug which runs under the radiator which is the wiring from alternator to battery.Very bad for corroding and make and break contacts as well.Check it oot and see if your car is wired this way.If so get rid of the multi-plug and replace with terminals.Also chaffs against body work here too.

Cheers mate, when I eventually work on it again

I'll give it a wee check and see how bad it is