I used a test light on my voltage regulator connector and it did not light up, I even replaced fuses but nothing so I was wondering where does the connector end up so I could replace the wire if it were cut? (I changed my alternator, battery and fuses after this video and it runs the same) 1998 2.5L

 

Welcome to the forum

Charging systems change by year so you should included year of vehicle in questions.

Alternators with internal voltage regulators are pretty easy to test

B+ terminal has largest wire, it is connected directly to Battery Positive via a Fuse or Fusible Link, so should always show battery voltage, 12volts, if not then fuse is blown

Internal voltage regulators came in 2 and 3 wire versions.

The 3 wire has a white wire that is a short jumper wire from regulators connector to another alternator connection

The 2 wire has that jumper wire inside the case, so only 2 wires are needed.

The remaining 2 wires are the Yellow wire which is also connected directly to the Battery via fuse or fusible link, so should have 12v all the time, if not then blown fuse
Depending on the year the B+ and Yellow wire will end up at the same place, in the engine fuse box(or on MEGA FUSE) or on the Starter relay post with Battery Positive cable

Last wire
The Light Green wire is the ON/OFF switch for the alternator/regulator, an important wire, lol.
With key off this wire will have no volts, OFF
With Key on it will have 12volts, ON

This wire comes from the BATTERY LIGHT bulb in the dash, and depending on the year it may have a separate fuse in the cab fuse box.

The way it works
When you turn on the key the battery light bulb gets 12volts, and its other wire(green one) is connected to the Alternator which is not turning now so it a GROUND, with 12v on one side and Ground on the other the BATTERY LIGHT comes ON.
So no Battery light with key on means a problem, either blown fuse or bad wire.

If Battery light is ON, then alternator has 12v on Green wire so it is ON
When you start the engine that 12volt from green wire is used as "startup voltage".

An alternator doesn't work by simply spinning it, it must have startup voltage to generate a magnetic field, then it can increase that voltage by being spun by the engine, so it makes more voltage than it uses AFTER initial startup.

Once alternator is producing voltage, say 14volts, then the whole vehicle is running on that 14volts, battery is not being used at all, it is being charged because it is only 12volts and system is now 14volts.
The Battery light now has 14volts on one side(from fuse) AND green wire(at alternator) is also 14volts now, alternator is working.
So Battery light is OFF, 14v-14v = no current flowing so filament will not glow, 14v-Ground = glowing filament, or 12v-5volt = barely glowing filament
Flickering battery Light means alternator voltage is dropping below 12volt(battery voltage), if this happens at idle it means diodes or fields have failed in the alternator, alternator can not produce enough voltage at lower RPMs to keep system above battery voltage level, so battery is being drained while you drive

 

Thank you ill check the mega fuse and its a 1998

 

1998 diagram below

Battery light does have separate fuse, if battery light comes on with the key then fuse is OK, and so is Green wire if it is plugged in at alternator end

 

Yeah it comes on but the yellow and white wire doesnt light up when I use a test light on it and my battery isnt charging also my green wire doesnt light up either but still shows on the dash