Cigar lighter often shares a fuse with other items. Fuse locations and specs can change depending on territory and trim level and so the supplied vehicle handbook is the best reference source.
As a result of rust, corrosion, a car wreck, or a defective part, your lock mechanism is not working.
The door must be taken apart and the latch mechanism inspected with a flashlight to see why it does not work.
You may also have to remove it completely to find the problem.
God bless your efforts.
