I have a 99 3.0 that is doing the same thing.

While driving I felt a jerk and the motor wanted to stall. I looked down at my cluster to find that my battery gauge was near low and my battery light was on. It died on me 5 min later. After getting it home I pulled the alternator. I exchanged it for another however, the problem persists. What I need to know is what fuses should I check and the locations of said fuses. I am by no means a mechanical kind of guy lol

 

Welcome to the forum

Go here and download your 1999 Owners Manual: https://www.ranger-forums.com/genera...1-models-3747/

It will have fuse box diagrams for engine bay fuse box and Cab fuse box

In engine fuse box is ALT SYS Fuse, 30 amp, check it, pull it out

On the outside of this engine fuse box is the MEGA Fuse, check it, use Volt meter, should have 12volts on each terminal, key off or on doesn't matter

If Battery light is on with key on then the cab fuse, #15, is OK

"New" alternator just means it was NEVER EVER TESTED, not "it works", so grain of salt on any "new" parts

 

Thank you for your response. Upon looking at the fuse diagram, I have found that #14 is the regulator. That is what the owner's manual says. I have not checked the mega fuse but I can certainly tell you that it is without a doubt a little corroded. In the engine bay what fuse should I be looking for. I have two 50 amp fuses in 1 30 amp. All of them are good.

 

Cab fuse box 15 is for Battery Light

Yes, 14 in Engine fuse box is for alternator, 30 amp, * mini fuse, this is not one of the bigger fuses

Disconnect either battery cable then clean the MEGA fuse terminals

 

I checked the 30 amp mini fuse. It was fine. I checked the mega fuse and decided to change it. Put everything back together and fired it back up and still no fix. Replaced every single mini and maxi fuse and still no luck. Went ahead and checked the cable going from alternator to the mega fuse and it was okay. Check the ground and it was okay. I have absolutely no idea what's going on here.

 

Key off
Use a volt meter to test battery volts, remember that voltage
Test voltage at alternators B+ wire, use alternators metal case as the ground
B+ is the larger wire(s) on the Stud/Nut terminal on the alternator, should see Battery Volts exactly, if not mega fuse or this wire is bad

Unplug the 3 wire Voltage Regulator plug on alternator
Test the yellow wire, should see Battery Voltage, if not then 30amp fuse or wire is bad

Test green wire, should see no Volts
Turn key on
Test green wire again, should see Battery Volts, can be slightly less because key is on, but above 12.2volts, if no volts then Fuse 15 in the cab is bad, but you would also have had No Battery Light, and you do, so fuse 15 is most likely fine

Check that the short white wire is plugged in to its single spade connector on alternator, unplug it and plug it back in

Plug 3 wire connector back in

Start engine
Test battery volts, should see 14+ volts, if not alternator is bad, new or not, its bad, not a guess

Charging systems are simple, test the 3 wires on the vehicle side, if they all test as OK but no charging, the alternator is bad

Auto parts shops can NOT test alternators, even though they do try

 

I did exactly what you instructed me to do. Nothing I did worked. I replaced positive wire from the alternator to the 175 amp megafuse. No change. So I thought maybe the mega fuse that I purchased was bad and I replaced it with another and it the vehicle runs perfectly. I guess I learned a valuable lesson that sometimes even fuses can be defective.

 

New used to mean "tested and works"

New now means "YOU test it, we will replace it if it doesn't work"