Yes they are supposed to. Better revisit the ground again. Grounds can be very weird. Good one minute, bad after vibration during driving, etc. To test the ground theory (after you are SURE the bulb is good) Find an absolute, or create an absolute, clean metal spot and attach a test wire to it and to the socket (not the socket contacts)and see if they light. The best, fool proof, place for testing is the battery ground post, but that is a long wire. Once you confirm it's a ground problem you can fix. If it's not, then set up a separate hot line to test. There are so many features in the "ground circuit" that it's better to use a separate wire to test. You can use continuity or test light testing but if not good with electrics, do the separate wire thing. That's my opinion. Your ground path is bulb to socket case, socket case to light housing, housing to body or frame, then to battery post. Depending how PO's have wired it, the path could have even more steps. Lots of places to be corroded, broken, rusty, loose... If you not sure at all about electrical, you need someone else who is or read up on it. It's hard to advise on this stuff on a forum if you have no experience. But if you are willing, so are we, just be careful that you know how the hot (positive) and the ground works to light a light and how the light has a socket, socket contacts and bulb has one or two filaments. Know how switches work to make various circuits hot.
