We have a fluorescent 2 tube fixture in our closet. I noticed a tube out so I replaced it. The tube flickered a bit but would not light, the other tube is lit. I turned the switch off to make sure the tube was seated properly, which I believe it is. The tube will still not light. However, when I tap the end of the fixture body the tube will light up. Turning the wall switch off and then on the tube will not light. I'm puzzled and don't know what to do. Any help you can give me will be very much appreciated.

Regards,
Bob

Try (2) new lamps...

Yes. That would be the ting to do. Sometimes the ballasts can be temperamental and need 2 new bulbs to fire properly.

Two new of the same brand and type.