I had the same problem with my Dodge Ram. The sending unit is probably bad. That part is in the gas tank, and is a pane in the neck to change. What I did was I found a similar truck in the junk yard and purchased the entire gas tank. I drained the old gas out, changed the tanks out, and filled it up. I have not had a problem since. The gas tank cost me $75 from the junk yard, and was fairly easy to switch out myself. Good luck.
As far as the brake light is concerned, you can get a new switch from the junk yard too. The switch is located on the brake petal, and is an east fix. Those are cheap new from the auto part store also if you would rather get a new one.
As far as the brake light is concerned, you can get a new switch from the junk yard too. The switch is located on the brake petal, and is an east fix. Those are cheap new from the auto part store also if you would rather get a new one.