Takes a little while to come on. When it does feels light the brakes are on lightly any suggestions

 

I don't remember for sure, but you may only have rear abs brakes on that truck. I'd go ahead and take off the rear wheel and make sure everything is in working order w/ the rear drum brakes. If you have front abs as well, go ahead and do the same on the front.

May not hurt to bleed the brakes while you are at it to make sure that isn't tripping the light, too.

 

There was a problem at one time with the sensor over the rear axle that caused the abs light to come on. You might want to check it out. It read the signal from the differential ring gear area.