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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Battery Light Nightmare

  • Thread starter Thread starter WrecklessHype
  • Start date Start date Nov 15, 2011
W

WrecklessHype

New Member
Nov 15, 2011
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0
Nov 15, 2011
#1
  • Nov 15, 2011
  • #1
I'm new to the forum and new to Mustangs, this is actually my girlfriend's car. She drives a 2003 GT 4.6 SOHC. I've searched all over about this and can't seem to pinpoint the issue.

It started like this:
Inspection time, service engine soon light on, failed inspection just for the sticker. Light came on for Idle Air Control Valve. Replaced that. New light for camshaft sensor. Replaced alternator with new OEM part from Rock Auto.

This fixed the ongoing issue with the car idling funny once in a while and also seemed to brighten up the interior lights, no more yellow lights inside! Ran great for a a few weeks, then on rainy nights, the battery light would intermittently come on and go off. It never stayed on more than a few minutes at most, sometimes would just flash. It's now consistently on then off, on then off while driving. It will cause the car to buck and feels like it loses power.

Checked the alternator, 14V, everywhere (battery light not on. Can't seem to get it to come on when it's idling) Checked battery, seems to only be at 59% charge. Pulled battery, charged for almost 2 hours, will only hold a 62% charge. New battery, charges fully and seems to hold a charge but the battery light issue remains.

Pulled all grounds by battery, sanded them down to shiny metal, check the ground cable under the car, everything seems to be grounded properly.

What am I missing?

Someone mentioned fusible link? Not familiar with this, where am I looking?
Contacting Rock Auto for a new alternator just in case.

Thanks in advance.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Nov 15, 2011
#2
  • Nov 15, 2011
  • #2
WrecklessHype said:
then on rainy nights, the battery light would intermittently come on and go off. It never stayed on more than a few minutes at most, sometimes would just flash. It's now consistently on then off, on then off while driving. It will cause the car to buck and feels like it loses power.
Click to expand...
Drive belt is worn, or the tensioner is weak. When the belt gets wet, it slips. The battery light comes on.

Do you have an uber sound system or other mods that increase the electrical load (bright lights?)? If so, this could make the slipping belt problem worse. At the least consider when it rains, the head lights and wipers are on. Both heavy load devices.
 

GDawg

Founding Member
Mar 22, 2002
1,469
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Nevada
Nov 17, 2011
#3
  • Nov 17, 2011
  • #3
In addition to what wmburns said, also make sure that the battery connectors on the battery terminals are TIGHT! You should not be able to spin them with your hands.
 
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