1999 Ford Mustang Charging system

Tiny
KINGCOBRAH99
  • MEMBER
  • 1999 FORD MUSTANG
  • 4.6L
  • V8
  • RWD
  • MANUAL
  • 78,000 MILES
On my 99 cobra I have a brand new alternator and battery. 14.5V comming off the alternator amd into the fuse box. However my battery is charging at 12.4-12.6V running with everything off. I am at a loss. As to where to look or how to test for the missing 2V. The alternator is working great l, my connections are great, the relays in the box are good. I juat have no clue where those 2 volts are going because only 12.5V are reaching the alternator.
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Tuesday, August 11th, 2015 AT 9:05 PM

7 Replies

Tiny
HMAC300
  • EXPERT
Check items in pic
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Wednesday, August 12th, 2015 AT 7:11 AM
Tiny
KINGCOBRAH99
  • MEMBER
I checked all of my fuses and they look good, is there something the the fusebox that regulates the volts comming out?
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Monday, August 17th, 2015 AT 11:51 AM
Tiny
HMAC300
  • EXPERT
Did you also check the fusible links in pic? The regulator is inside the alternator. Test fuses in pic with a test light not "they look good". If a fusible link is burnt up it will not charge nor will the one fuse get any power.
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Monday, August 17th, 2015 AT 12:03 PM
Tiny
KINGCOBRAH99
  • MEMBER
I mean they look good as in no corosion on the tips and the arch on the inside is still connected and there was no resistance what I tested them. I dont see those fuseable though.
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Monday, August 17th, 2015 AT 1:33 PM
Tiny
HMAC300
  • EXPERT
They are right on the power dist box where the battery cable connects to it. Check with a volt meter the color of wires are shown in pic they should have 12 volts each side or whatever your battery voltage is. Twirl them around as you test
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Monday, August 17th, 2015 AT 3:48 PM
Tiny
KINGCOBRAH99
  • MEMBER
I couldnt find anything wrong. Took it into the ford dealership and they tested everything and said there was not a problem. Got one start out of it then it died. Autozone replaced my battery and checked the system and it says my voltage regulator is bad. Thats the same issue that the first alternator had and why I replaced it. So I had autozone bench test the old alternator and it passed with flying colors. So that leads me to believe that the wiring is bad. I followed the three wires comming out. Of my internal voltage regulator and found that the white and black wire is 8in long then it just ends. Someone had electrical taped it and put some glue on the end. Now I had this car for 7 months with no issue and same wiring setup. But every electrical diagram shows that the white and black wire from the voltage regulator should be attatched back to the alternator. However it was not on the old alternator and there is no spot for it anywhere on the old or new alternator. I believe that is the wire that is causing these issues but I have no clue where it would be attached.
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Sunday, August 23rd, 2015 AT 3:22 PM
Tiny
HMAC300
  • EXPERT
Our diagram doesn't show like yours but the black white wire terminates in engine harness meaning it'snot connected anything. If you alternator has markings like what is shown in my drawing this is where the wires go. See pics for further testing. Is the bulb any good? Also there is a resistor there that may be bad or the cluster may be bad. One other thing, use another volt meter to see if yours is screwed up.
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Sunday, August 23rd, 2015 AT 3:43 PM

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