I have a bathroom light that was installed in 1953, when the house was built. In all of the bathrooms, a 4-light medicine cabinet was installed above the sinks. One of the two side lights has stopped working and I can't access the medicine cabinet(has two of the left side lights) to check the wiring and can't remove the cabinet without major damage to the surrounding plaster. I can post a photo if this post is allowed, to show the problem. Any advice would be appreciated.