Buy a new sump pump. If you are worried about it, you should always unplug it and have a professional look at it....so they can sell you a new one.
The contacts always sit around in dark, moist environments, the switch is probably bad and has made a connection through somehow. If that is bad, there are most likely other issues. Get a new one , you do not want an issue when you need this thing to work.
Go to a plumbing supply house and get the latest and greatest, with a backup alarm, and battery pack if you get lots of water.
It will be cheap insurance compared to a flooded basement.