I’ve been having electrical problems with my charging system, I just replaced my mega fuse and I thought that it had fixed the problem now I’m having trouble with the battery light coming on while driving and the voltage dropping on the battery gauge. I read that a loose belt could cause that so I tightened it and made sure all battery connections were corrosion free and snugged down. Open to any help or suggestions.

 

Welcome to the forum

Battery light on dash does two things
1. It is the Start Up voltage used to get alternator working, so on/off switch for an alternator
If battery light doesn't come on when you turn the key on then alternator will not work

2. It monitors alternators voltage when engine is running
A car battery has 12.3 to 12.8volts, below 12.3volts is a failing battery

An alternator has a set voltage range of 13.5 to 14.8volts
So when alternator is working the WHOLE VEHICLE is running from alternator electricity, Battery's only purpose is to Start the engine, thats it

If alternator is at 13.5volts then battery is being charged, maintained, just after start up alternator will output 14.4-14.8volts to Fast Charge the battery in case engine stalls
After a few minutes alternator will drop voltage down to under 14volts so battery doesn't get "cooked", it is very bad for the battery to get over 14 volts for very long

IF........alternator voltage drops below Battery voltage then Battery Light will come on, just like when you turn on the key, Alternator is at 0 volts, battery 12.5volts, so Battery Light is ON
Flickering Battery Light means alternator voltage is dropping below battery voltage off and on.

You can test 3 wires with a Volt Meter to determine if it an alternator or wiring problem
FIRST test battery voltage, engine off

On the back of the alternator is the B+ terminal, stud and nut, test its voltage, should be EXACTLY battery voltage, if not then connection at Mega fuse is bad

Pull off the 2 or 3 wire connector on alternator
YELLOW wire should have Battery voltage exactly, if not then ALT Fuse in engine fuse box is blown

Light Green wire should have 0 volts
Turn on the key/engine off
Light Green wire should now have Battery voltage, could be .1 or .2 less that's OK, this is the Battery Light wire, just FYI

If all 3 wires test OK, then alternator is bad, but lets test that
Plug alternator connector back in
Start engine
Test battery voltage again
Should be above 14volts, if not then alternator is bad

 

I’ve been going through testing everything you listed above, and have encountered another area that I need some advice on, I tested the light green wire that runs from the alternator; the one that controls the battery light and it was supposed to read at 0.0 and it’s reading at 1.9 to 2.0 volts what could this mean?

 

That is OK, its not actual voltage, it's a phantom voltage, no amps, depends on the wiring in your volt meter

Connector unplugged
Green wire 12v key on, under 3volts key off