You talk of lamp holders plural - suggesting at least two.
One lamp holder might have failed but it would be a very big coincidence for two to fail at the same time.
It would be reasonable to assume a common failure that affects both lamps - a fuse you don't know about - a wiring problem - a switch broken or in the wrong position. It needs to be looked into.
As for your question - could you do it yourself - I would guess very unlikely but not impossible.
Good Luck..., November 2015
