Battery light on

Tiny
FRIMLIN
  • MEMBER
  • 2002 FORD FOCUS
Hi, I've got a 2002 Ford Focus ZX3, manual transmission. Battery died, so I replaced it, but it wasn't charging properly so replaced alternator.

Now the battery light comes on while I'm driving. Went back to where the alternator was replaced, they tested the battery and said it was charging properly, alternator was good. The battery light didn't come on for them. But the battery light still comes on intermittently while I'm driving.

Just in case, I want to mention that when I bought this car used several months ago, the radio was broken, so I replaced it with a non-Ford radio. Could this have anything to do with the battery issue?

Appreciate any help.
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Tuesday, July 10th, 2007 AT 7:47 AM

27 Replies

Tiny
NANIMO
  • MEMBER
It sounds like the alternator is out but to be sure let check out his guide,

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please run down this guide and report back.
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Thursday, March 21st, 2019 AT 7:06 PM
Tiny
CGSCHEIBE
  • MEMBER
  • 2002 FORD FOCUS
  • 4 CYL
  • FWD
  • MANUAL
  • 57,000 MILES
The dash battery indicator light came on today while driving. During the drive home the light was coming on and off. Checked the voltage at the battery with the enigne running and light on and got 14.4 volts. Cleaned the connections and tried a different battery but the light remains lit. Car starts and runs fine and voltage while running seems correct. Any ideas what could be wrong?
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
JACK42
  • EXPERT
The light signal comes from the PCM. Might want to check/clean connections at the alt plug- blue and gray are the PCM data lines. Also check the black/blue wire behind the right kick panel- dash ground.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
SOKRAT GEGA
  • MEMBER
Hi
The problem is voltage regulator in your alternator replace and the problem is fine
Sorry for my bad english
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
CATASHEVILLE
  • MEMBER
  • 2002 FORD FOCUS
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 60,000 MILES
The battery light on the dash has recently been coming on while driving my 2002 ford focus wagon. As of today, the light does not turn off. I took the car in to the local mechanic who tested the battery with a voltmeter. The battery is just about one year old. The meter would jump from undercharging to overcharging and sometimes rest in the 'ok' area (sorry, I don't know the numbers). Without any further diagnostics I was told it was most certainly a faulty alternator = $300 or so. I am not looking for a cheaper solution, but a firm believer in "measure twice cut once" and want to be certain that all possible troubleshooting is performed before shelling out the bucks.

I have a couple of questions:

1. Can they test the alternator before replacing it to be certain it is the alternator that is causing the "jump" of the volts? And, if so, what would one look for when they are testing it to determine it is faulty?
2. Does the alternator regulate the volts going to the battery?
3. If not the alternator, what else could cause the volts to jump?

Any wisdom would be greatly appreciated.

Cat
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
You can check the alternator with a volts meter
I would suspect bad alternator from your description
but you need and should check battery terminals and alternator terminals and wiring
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
SOKRAT GEGA
  • MEMBER
Hi
Check voltage must to be 14.4 volts max not more if the voltage going 15 or 16 volts the problem. Is alternator you can repair just to change voltage regulator and diodes
Sorry for my bad english
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
BINGAS
  • MEMBER
  • 2002 FORD FOCUS
  • 4 CYL
  • 58 MILES
Battery lite on alt charging at 14.5volts
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
If the battery is going dead, check fuseable link. If it isn't going dead, check alternator diodes. If that is good, check for body ground issues. Another circuit may have lost its ground and be grounding through that light turning it on.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
COLTHARP
  • MEMBER
  • 2002 FORD FOCUS
  • 157,000 MILES
Their is a clicking, clicking sound that comes on when driving and some times it make the battery light come on. Battery is good, changed two relay switches and a fuse already, changed the terminals on battery. It's not the alternator, it was replaced 2 yrs. Ago. The radio and lights still work when the clicking is going on, although if driving at night the headlights will flicker when the clicking starts. It the door indicator is on, due to door not closed all the away, when the clicking starts, then the indicator light will flick off and on at the same time, to the same beat of the clicking. We have checked every thing we know and have gone through the Ford book.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
FIXITMR
  • EXPERT
Does it do it while standing still or only when driving? And does it matter how many electrical items are turned on? Have you checked battery voltage when this occurs to see if it is steady around 14v?
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
COLTHARP
  • MEMBER
Yes it does it even when I'm at a light, I'm afraid the car will die. Some times if it keeps going off alot and fast I will turn off the radioe and heater to see if it stops and it still does it just maybe not as fast. When the battery was checked it showed 15 the car was running and the headlight on and radio on.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
FIXITMR
  • EXPERT
When vehicle is stopped can you determine the location of clicking? Is it very loud? 15+ volts to me is a high reading bordering overvoltage which may have effects on electrical parts.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
FIXMESCOTT
  • MEMBER
  • 2001 FORD FOCUS
Electrical problem
2001 Ford Focus 4 cyl Front Wheel Drive Automatic 160k miles

The battery light on the dash came on today. I don't a book on the car. Car cranks fine.
Thanks.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
2CEXPT
  • MEMBER
HI fixmescott and welcome to 2carpros

Get the alternator and battery load tested and comeback with the test results-this is where we start
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
CONVERTGIRL
  • MEMBER
  • 2001 FORD FOCUS
2001 Ford Focus 4 cyl 260000 miles

i just had a new alternator and battery put in, half way home the battery light started flashing. What now?
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
M_H_RITZEL
  • EXPERT
If you had not had that problem before I would take it back and have the altinator checked for output. In this line of work I have seen altinators go bad shortly after insatlled. Before you go back check the wires and make sure they are connected tightly. Some times a wire is loose or connection is not tight. If you can't find a wire loose then take it back where it was repaired and have them check it out.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
CONVERTGIRL
  • MEMBER
Thanx, the light was on before, so I took it in and they said I needed an altinator and that the battery had drained because the altinator was bad. But then light came on again on the way home. It was late so I just drove home. I checked this morning, it still starts up, but the light comes on again.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
M_H_RITZEL
  • EXPERT
With them putting a new altinator in and the light coming back on I would still take it back and have it checked. I have seen brand new altinator being bad when they were put on. Not saying this is the case. Since they had put the altintor on they should check it to make sure it is charging enough.
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Friday, June 12th, 2020 AT 12:20 PM (Merged)
Tiny
MARIE CHISHOLM
  • MEMBER
  • 2001 FORD FOCUS
Electrical problem
2001 Ford Focus Front Wheel Drive Manual

iv, e got ford focus zetec tddi, battery light is on constant, iv, e had alternator reconned
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Friday, June 12th, 2020 AT 12:20 PM (Merged)

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