frustrating electrical problem need help bad

[nads123321]

New to this site and doing this on a phone so sorry about my typos ahead of time. I have a 1999 Explorer AWD 5.0 v8 and I am not getting a charge it seems like from the alternator. I put a reman one on and 2 shops said it was junk so I went and bought a new one not reman bran spankin new! Lol. New battery 850 cold amps also just had it towed to a shop and they said it was the starter so there is also a new one of those. The feller at the shop said he was for sure it was the reman alternator that was bad. So today I put the new one on which that means 2 alternators this week! And still I am getting no charge. battery was fully charged before I started it with this new one. drove it a while. parked it battery is dead. had the battery tested at 2 places and tested great. I at a lose here guys. Help me. thanks!

 

[eDge2k]

See if its even charging first, crank the truck and while running, disconnect (safely) the positive side of the battery, if it stops running, the vehicle is not charging and you can at least rule out for sure weather it's the alternator or not.

 

[2000StreetRod]

voltage measurements?

Measure the battery voltage with engine off. If the battery is charged it should measure about 12.5 volts. Start the engine and measure the battery voltage. It should measure about 13.6 volts. If it does, then assume the alternator is charging the battery and there is a drain on the battery when the engine isn't running. If it doesn't, then measure the alternator charge terminal to ground voltage. If it measures about 13.6 volts then check cable connections from alternator charge terminal to battery and battery connection to ground. On my 2000 Sport the alternator charge terminal goes to the Mega fuse mounted on the battery junction box.

Charge current flows thru the Mega fuse to the battery. Check the Mega fuse connections and make sure the Mega fuse isn't blown. My stock battery ground cable was tiny with a small ground terminal. Check that.

If the battery voltage is adequate when the engine is running then find out what is drawing current when the engine is off. One method is to connect a battery charger to a fully charged battery and read the current draw on the battery charger. Pull fuses until the draw is eliminated.

 

[DjDom]

Yeah, I'd go with a bad connection somewhere between the battery and alternator. Make sure all the connections are secure and not corroded. I doubt that you've gotten 2 bad alternators.
Reman alts should be just as good as new ones.

 

[nads123321]

Going to check that fuse today after work. I hope and yet I'll be pissed if its something that simple lol. thanks for the help and input. I am an heck of a mechanic I am a Boeing helicopter mechanic by trade but this electrical crap gets me every time ugh

 

[koda2000]

1. does your BATT/CHARGE idiot light, on the instrument cluster, work during the bulb check? if not, your alternator will not charge because it's not getting turned on. the voltage regulator mounted on the alternator turns off the BATT light when the engine is started by interrupting the ground connection for the light (green/red wire). if the light is working normally, proceed to step 2.

2. check voltage on both sides of the mega fuse with the engine running. should be 13.6 + volts. if you get something close to this on only one side, the fuse or connection is bad. if you don't see 13.6 + volts at either side of the mega fuse, check for voltage at the "B" (large) terminal on the alternator.

let us know what you find and we'll go from there.

 

[PhantomFord]

run a piece of wire from the positive terminal on the battery to the exciter wire on the alt then see if your voltage gauge comes up. the exciter is the connector going in to the alternator with the one solo wire

 

[my white eddie]

I went through this right after I got mine. Follow the green wire w/ red stripe from the alternator towards the firewall. Chances are you will find a scuff or flat out break in it. Mine was bare right before the big bulk head connector
at the rear of the engine. Just guessing but your BATT light is not on is it?
That's a clue right there. Just my .02 for what it's worth

 

[koda2000]

I went through this right after I got mine. Follow the green wire w/ red stripe from the alternator towards the firewall. Chances are you will find a scuff or flat out break in it. Mine was bare right before the big bulk head connector
at the rear of the engine. just my .02

yes, i recall your saga and you're correct green/red wire. i've corrected my post.

 

[my white eddie]

I don't know if I like being recalled as a saga! lol. It was an adventure to say the least. Hey I'm finally a productive member of this society. YEAH!

 

[nads123321]

Update new mega fuse and still hasent fixed the problem. I will do the other check on it tonight and give another update in the morning

 

[eDge2k]

1. does your BATT/CHARGE idiot light, on the instrument cluster, work during the bulb check? if not, your alternator will not charge because it's not getting turned on.

X2, I had this happen once, I removed the gauge cluster to put some lights in it and had to run to the store, got half way there and truck died on me in the middle of the road, I ended up jumping the 2 wires together to get by until I finished the lighting, was pretty embarrassed.

 

[2000StreetRod]

fuse 14?

You might check fuse 14 in the battery junction box. It supplies power from the alternator charge terminal (armature) to the voltage regulator. Did your stock alternator look like the one below?