antilock light

1990 f150 4x4 5sp my antilock brake light is on why

Take tire off of rear, then take off the drum cover. Look for anything that is unusual. It may just be that your rear drums need to be replaced. (if you know nothing about drum brakes or brakes in general i'd suggest you take it to a local mechanic.)

1990 f150 4x4 5sp my antilock brake light is on why
thank you i tried to pull a drum it was to tight ill let you know when i get it off

If its a little tight, it may be because rear drums have never been replaced. If they havent there will be a little plastic fitting around the stud up against the drum cover. Take a screw driver and pry that off. If they have been replaced then i would try to wiggle and try to loosen witha flathead. also if you have an air compressor blow off around the edges, there may be dust and dirt around there preventing you to remove it.