There's no warranty seal on it. They won't know if you've opened it or not, and you might save yourself the trouble of sending it back if you do. It's not uncommon for the little black bar to have unhooked from one or both of the solenoid pins. You can look at the working side to see what the non-working side should look like. If they both look the same, then there's another problem. If one looks wrong, see if you can fix it. Also, look/feel for anything that might be holding it from moving, such as some glue that got in the wrong spot.