my battery light stays on while driving.
battery checks out good and I replaced the voltage regulator and cleaned the terminals.
I heard there is a mega alternator fuse 1.75 amps I cant locate it.
could this be the problem?



thanks
Halloween.

 

Battery light circuit is pretty simple, bulb gets 12volts when key is on and bulb is grounded by voltage regulator, so it comes on when alternator/regulator is not working

When you start the engine and alternator starts to make voltage it is no longer a Ground so Battery light goes off

So not a Mega Fuse issue, 175amp by the way, its on the outside of the engine fuse box, this fuse is for alternator OUTPUT, not part of the Battery Light circuit

You need a volt meter to test any charging system
But in the mean time check ALT SYS Fuse in engine fuse box, 30 amp, unlikely problem but check any way

Key OFF
Unplug the 3 wire connector on alternator
Turn the key ON
Battery Light should be OFF, if not then there is a short to ground on the Light Green wire on the 3 wire connector
Green wire is the ground for Battery Light bulb, so when unplugged Battery light should be OFF, this wire also provides Startup Voltage for the alternator, so if its shorted to Ground then no Startup Voltage so no charging

On the 3 wire connector is a Yellow wire, it should have 12volts key on or off, that from the ALT SYS 30amp fuse
Green wire should show 12volt key on, 0 volts key off

On the back of the alternator is a Stud with nut connection, this is called the "B+" connection, it should show 12volts key on or off, this is connected to the 175amp Mega Fuse

If you have:
12volts on B+
12volts on Yellow wire
12volts on Light Green wire key ON, 0 volts key OFF

And battery light stays on then replace alternator