charging system

Sir-check the alternator fuse 20 amp and fuse no.5 15amp. Below is your charging system EWD

Thanks alot for all the wonderful knowledge, I didn't know where the fuse's where but I knew it had some. I replaced the 20 amp, the 15 amp was good. However, it still isn't charing. I'm ready to replace the battery as it has been on the charger quite a bit now. Also, I have a high output Alternator that spent some dollars on and would like to use it once I get this thing charging, will I need a high output Alternator kit to connect it. I have other issues's with the electrical but I will do them one at a time. I also had a CD for my mustang with all the wiring and troubleshooting but dont know what happened to it. This is a great place for knowledge. You help is always appreciated.

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.

check items in pic

I checked all of my fuses and they look good, is there something the the fusebox that regulates the volts comming out?

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.

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.

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

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.

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......

Have replaced with new battery. Have replaced altenator (thought it ws bad took it back and exchanged for another). SO new altenator; new battery. Altenator will not charge battery. Have replaced battery terrminals. Battery light stays on at dash and car runs off battery until it discharges. No voltage difference (stays at 12.5v) with car at 2000 RPM. What else is there? The only thing I can think of is to replace the ground cable amd the hot cable or the wiring between the altenator and the fuse box. Next Check the ground strap from the engine to the chassis. Could it be the hot lead going to the voltage regulator? It is the 3 pronged lead with the middle lead going to a fourth pin (i read nothing on that lead with volt meter). ALso the altenator has bench tests good.

check to make sure the alternator is hooked up properly and all cables are clean of corrosion. check the wiring harness for damage also, get back to me.

Thanks. I did all that up top. I have not gotten under the car and checkec the other ends. I even scraped teh terminal fittings. It seems to me that for some reason the voltage regulator is not geetting a signal that the battery needs charging. There are three leads going into hte voltage regulator. what kind of voltage or ground should i be seeing on those leads. I know the middle lead goes over to a 4th terminal right next to the 3 lead connector. As far as the large cables I even replaced the connectors on the ground and posative.

for some reason my online diagrams arnt loading tonight, you will have to remind me tomorrow to look for them!

OK!! I should have worn glasses!! The problem was no voltage on the yellow lead going to the voltage regulator. Stripped and cut the wire into. Traced it with a toner. Went to the fuse box. Found the fuse. IT WAS BLOWN!. I chedcked those fuses 6 days ago(twice) and did NOT appear to be blown. My son came out last night and checked the fuses with a toner and fond the blown fuse. I expalined I checked them. He asked if I was wearing my glasses.... NOooo!

All is well except for an embarrased dad.

thanks, so much for your help.

ouch! i hate it when that happens but then again you could have blew it when you replaced the alternator or battery after you had checked it! remember that!

glad to hear it was a simple 15 cent fuse

i have a 1997 mustang gt with a 1999 mustang gt PI motor. i just bought a new battery and a new alt, and my battery is draining FAST!! and i can not find the problem at all. me and my dad did a test on it and its running over 50 milla amps is you connect the -post to the cable. please help

50 milli amps is ok. over 150 is an issue.

how fast does the battery go down??? what is the voltage at the battery with the engine running??

Roy

yes i have a 1999 mustang gt and rite now it is charging way to much but after awhile it goes down! i replaced the alternator also the battery and it didnt help at all

Use a digital voltmeter to measure the battery voltage when the overcharge is occurring. If it's between 13.75 and 14.75 volts, it's working properly. If it's high, the voltage regulator is at fault. It's bolted to the back of the generator.