My generator light slowly comes on when ever im at an idle or push in the clutch. I checked the voltage of my battery while off and running and the voltage is good and the generator is charging the battery.

 

Have you checked the battery voltage while the generator light is on and while it is off?
The alternator can have a internal fault in the control/sensing circuitry and still output the correct voltage.
Your truck is to old for any info to be listed on the Ford site so I cant see how the internal wiring works.

 

I’d be curious as to idle/cruise voltage too.
Make sure the idle speed is spec as well.

My old Rambler would suffer a flicker/dim gen light at idle , and adjusting the regulator a tad cured the issue..