Check battery light help

pong · 11-01-2009, 10:25 AM

Hi all,

My girlfriend had a 2004 Mustang convertible and we are having problems with her check battery/charging light coming on intermittently. It has been coming on and off at random times for about 2 months, sometimes it flashes, sometimes it stays on for a period of time, and sometimes it doesnt come on at all. She has a long drive to work and I dont want her to break down on the highway since we work different shifts.
I replaced the battery about 30 days ago because it still had the original in there. Battery light still randomly came on so I took the alternator out and have taken it to 3 different auto part stores, had it checked now 6 times, and every time I have been told it is fine. Its been doing this for about 2 months now and the car runs, starts, and idles fine. I tried running with all the accessories(lights don't seem to ever dim), and I also disconnected the battery while the car was running and the car kept going so I really feel that the alternator is fine.
Could it be a bad sensor setting the light to go off. If that is the case is that hard to replace?? I want to replace the sensor if it bad because then she would never know, if their really is a problem, if its real or not. Or could it be something else setting it off? By the way her car has 67000 miles.
Thanks for any help...

PONG

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sIx · 11-01-2009, 11:23 AM

Battery light is more than likely the Alternator. Seems unlikely that the brushes are worn at 67k miles, but a diode could have gone out, or maybe the voltage regulator.

I'm willing to bet money thats what it is.

brent4 · 11-01-2009, 11:59 AM

^ he said he has already had the alternator tested..i think that it could be a sensor or a connection to the battery that wiggles lose.

neo8222 · 11-01-2009, 12:50 PM

yeah check all the cables for corrosion, rust, and tightness

sIx · 11-01-2009, 12:54 PM

Quote:

Originally Posted by brent4

^ he said he has already had the alternator tested..i think that it could be a sensor or a connection to the battery that wiggles lose.

I was tired and missed that part

pong · 11-01-2009, 01:56 PM

Thanks guys... I'll double check the cables for rust/corrosion/tightness although I didnt see anything when I initially changed the battery. I'm not much of an electrical guy, if its the sensor is it hard to replace and do I need to cut any wires or is it plug and play?
BTW... I gotta come clean and say that I'm a Pontiac guy(got a 2004 GTO and a 1991 GTA) so I really appreciate the help... please dont flame me.

PONG

brent4 · 11-01-2009, 02:20 PM

Any mods done to your goat?

pong · 11-01-2009, 02:40 PM

Quote:

Originally Posted by brent4

Any mods done to your goat?

Pretty much stock right now except for exhaust. Have some headers coming in soon so that will be my next mod.

PONG

pong · 11-02-2009, 07:22 AM

Anyone might have any experience changing the sensor on the stang, I don't know where to begin..

PONG

neo8222 · 11-02-2009, 06:39 PM

FLAME!!!!

RAAAWWW lol but really the voltage regulator would be simple unplug, unscrew, and pop off i could tell you where the sensor is but i cant find my schematics for the mustang. if i find my book before anyone else posts where it is ill edit it in.