My 2002 Ranger 2wd auto. has the ABS light on. I am attempting to fix the issue but is it safe to assume that since the light is indeed lighted all the fuses or any relays' are working
I am installing all 3 speed sensors and a different module/pump assembly. That's pretty much the whole system isn't it? Other than wiring of course.

 

ABS light will come on if brake lights are not working, i.e. bad brake light fuse or switch

If brake fluid is low ABS light can come on, usually brake light on dash as well.

ABS light itself gets 12volts with Key on from a separate fuse
ABS Module Grounds the bulb to light it up, on power up module ungrounds bulb
So if ABS module lost power ABS light would come on because module was not actively ungrounding it

Wiring diagram here

 

Horray, the light went out with the above parts, I pumped new fluid through the system while bleeding the brakes and didn't do anything special as far as abs bleeding. Light now works normal.

 

ABS light is now out with the new parts and a normal bleed

 

Good work