01 Mustang GT battery light won't go off

Asked by Feb 26, 2016 at 09:54 AM about the 2001 Ford Mustang GT

Question type: Maintenance & Repair

Battery light will not go off. Alternator shows charging  13-14 volts running, battery shows 13 volts with motor off. When I unplug the connector in photo, the battery light goes off but alternator drops to 12v and so does the battery. Plugging the connector back in turns on the battery light and there is an audible change in the sound of the alternator. according to the schematic, the connector has a light green/red wire that goes to the battery light and a yellow/white stripe wire that goes to the under hood fuse box. Is this a wiring issue or is there something going south with the alternator/regulator?

4 Answers

247,175

Alternator should show 13.8V -14.2V if working correctly and battery should be around 12.5V. Not sure what you have going on, maybe someone else will chime in. Maybe remove the alt and have your local auto parts store test it?

4,965

A battery light indicates your system is discharging. First place to look would be the alternator so, I agree with "Tom" - have the alternator checked out before anything else. I believe the connector you are pulling out controls the "Battery" lamp on your dash so I would expect the light to go out when you pull the plug. One other thing, are you sure your belt is tensioned properly and it is not slipping?

1 of 1 people found this helpful.

The belt is tight and no signs (or sounds) of slipping. It seems to be charging OK even with the connector for the battery light and the wire that goes to the fuse block unplugged. Wife drove it to work and back and I checked the battery, showed about 12.5 volts. Doesn't seem like there's any charging issues...just a battery light that won't go off unless it's unplugged. I have never had an alternator that "kind of" worked out. . I thought they were more like "it works fine or not at all".

I have / had similar issue. I had bought a used 2000 GT, it was in a bad state. The alternator had only 2 wires and the light was on. In all the places I have checked it should have 3 wires running into it. Yellow, White and Green.

Your Answer

Add photo

Related Questions

  • 01 Mustang GT battery light won't go off 4 answers

    Battery light will not go off. Alternator shows charging 13-14 volts running, battery shows 13 volts with motor off. When I unplug the connector in photo, the battery light goes off but alternator dr...

    2001 Ford Mustang GT

    -

    Maintenance & Repair

  • My mustang battery gauge go down when I stop at a light 12 answers

    I have a new alt and battery and the problem still there. Anyone know what it could be?

    2006 Ford Mustang GT Deluxe Convertible

    -

    Maintenance & Repair

  • Why won't my 02 mustang gt start 4 answers

    I've had the car almost a month got to drive it 2 weeks and went out to start it one morning and it acted like battery was dead so I tryed jumping it and nothing. Came home from work later and jum...

    2002 Ford Mustang GT

    -

    Maintenance & Repair

  • mustang dome light issue 1 answer

    01 Mustang GT dome light doesn't go off when the doors are closed. Will not turn off with headlight switch either. Stays on all the time.

    2001 Ford Mustang GT

    -

    Maintenance & Repair

  • 1994 mustang 5.0 GT battery and fuel pump 1 answer

    If my 1994 5.0 gt mustang has been sitting for a few years without a battery when i put a new battery in it do i need to reset the fuel pump switch?

    1994 Ford Mustang GT Coupe

    -

    Maintenance & Repair

Mustang

Looking for a Used Mustang in your area?

CarGurus has 44,482 nationwide Mustang listings starting at $1,500.

ZIP:

Search Ford Mustang Questions

Ford Mustang Experts

#1 Tom Demyan
Tom Demyan
Reputation 4,500
#2 Bob Beaman
Bob Beaman
Reputation 1,240
#3 COMETGUY61
COMETGUY61
Reputation 1,090
View All

Related Models For Sale

Used Chevrolet Camaro
370 Great Deals out of 31,228 listings starting at $2,500
Used Chevrolet Corvette
218 Great Deals out of 22,159 listings starting at $3,750
Used Ford Mustang SVT Cobra
4 Great Deals out of 212 listings starting at $5,500
Used Ford F-150
2,091 Great Deals out of 192,324 listings starting at $290
Used BMW 3 Series
1,022 Great Deals out of 31,416 listings starting at $1,000
Used Jeep Wrangler
274 Great Deals out of 15,789 listings starting at $3,795
Used Chevrolet Silverado 1500
1,935 Great Deals out of 182,334 listings starting at $999
Used Honda Civic
831 Great Deals out of 83,702 listings starting at $750
Used Honda Accord
1,053 Great Deals out of 66,933 listings starting at $1,000

Used Cars For Sale

2017 Ford Mustang GT For Sale
8 Great Deals out of 4,672 listings starting at $26,500
2016 Ford Mustang GT For Sale
591 listings starting at $24,950
2015 Ford Mustang GT For Sale
8 Great Deals out of 579 listings starting at $23,500
2014 Ford Mustang GT For Sale
6 Great Deals out of 436 listings starting at $13,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.