Tractor Repair: battery, ground cable, test light

Question
i bought a older jd tractor,i conected wire to fuel sending unit that was loose,now battery will not hold charge could this be the problem with battery not holding charge

Answer
 Can't say for sure without doing some tests first.  With everything on the tractor shut off, remove the ground cable from the battery and hook up a test light between the cable and the battery post.  If there is a draw that is taking power from the battery, the test light will light up.  By disconnecting wires, pulling fuses, etc. you can narrow it down by the process of elimination.  When you disconnect something and the light goes out, you found your draw.  It's also possible that your charging system isn't working or the battery is bad.