Lighter socket doesn't work, not the fuse.
#3
Ungrounded Moderator
iTrader: (4)
Basic diagnostics 101. Unplug the connector on the back of the socket. Use a test light or multimeter to test for power on the center terminal. If no power go back to fuse panel and test both input and output sides of the fuse socket. Power at fuse but not at socket means broken wire between them (assuming you've tested the fuse as well).
Similarly, test the ground terminal of the lighter socket to ensure that there is a good ground.
Similarly, test the ground terminal of the lighter socket to ensure that there is a good ground.