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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 46456
Experience:  16 years experience
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04 mustang not charging battery

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04 mustang not charging battery
Have you checked and had the battery load tested?
Customer: replied 7 years ago.
yes battery charges well and tested ok, car will start well when battery charged but drains quickly when running. also battery gauge in dash showing low while running
Then either there is a heavy draw or the alternator is lacking voltage or amperage output. Can I have a VIN # ?
Customer: replied 7 years ago.
not with car at this time. it is an 04 mustang gt with a single overhead cam 4.6 engine. also if I pull a battery cable when engine is running it will die
Get back to me with the VIN...I can see alot more with that.
Customer: replied 7 years ago.
I dont have the vin #, I would like to here from someone else or to decline the answer and withdrawl my funds

Hello Horacee


I'm Chris, Thanks for allowing me to help you here on Just Answer.


Do you own a DC volt meter and battery charger to do some tests for me?

Customer: replied 7 years ago.
yes I have a multimeter i use for work. what test do I need to do?

Charge the battery for 6 hours or more on 6 amps or less. Now let it sit another 6 hours disconnected whats the voltage (DC)__________


Now immediatly hook up the battery cables, what is the voltage___________


Hook the battery up and turn the headlights on for 1 minute then back off for 1 minute whats the battery voltage_______


Now start the car and let it idle for one minute with nothing electrical running wahts the voltage at idle _________


While idleing turn on the headlights and wipers and rear window defrost and blower on high, whats the voltage____________


Copy and paste this in your response and fill it in.

Customer: replied 7 years ago.
hi moose, i worked a 12 hour shift today so i will charge the battery tonight and run the test tomorrow. I did charge the battery all day yesterday at 2 amps and drove the car when i got home from work. made it about 5 or 6 miles with lights and heater on high before the battery gauge started falling much, turned heater off and headed home, was losing lights and car wouldn't restart at end of trip. the battery seems good but I will run the test and get back to you. another piece of info, the engine was replaced about a month ago. is a loose ground wire somewhere a possibility? Horace
Hear from you later
Customer: replied 7 years ago.

charged battery 12.5 volts

connected battery 12.5 volts

lights on one minute, off one minute 12.4 volts

idle car one minute nothing on, 12.1 volts at idle

at idle turn on lights , wipers, rear defrost and blower on high, 11.4 volts

OK your battery is not charging at all. At idle it should be about 13 volts and with accessories on you should be around 14 volts.


This vehicle has a internal regualtor in the alternator so you dont have to look in to a computer concern here. You either have a fuse blown or wire issue or faulty alternator. There are a few tests to do here along with some explaining info from ford .Click here for this info and click here for the alternator test. Ford calls a alternator a generator so dont get worried when you see the word generator.




Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 46456
Experience: 16 years experience
Chris (aka- Moose) and other Ford Specialists are ready to help you
Customer: replied 7 years ago.
Thanks Cris, Thats about as much info as I could expect. I've already checked the fuse. So I will run the tests and go from there. And I'll mark you as my ford source. Horace
Your welcome
Customer: replied 7 years ago.
hey cris, found connector unplugged under battery junction box. thnaks again
Good job.