Installed a Nicro 3" AFI Day/Night Plus Vent Stainless - N20703S on 2017-06-18. Worked till the end of last year. Opened the unit up today. One of the two remarkably small wires (26AWG?) was cut in two ... guess from the solar vent being stepped on. Appears there is no clearance for the wires between the solar cell and the body of the unit. There is some soft, clear, tacky material on the back side of the solar cell. To make it worse the "+" and "-" symbols by the battery are raised, creating edges to cut the wires, and further reducing the space available, rather than depressed.
After reconnecting the cut black wire (negative, white is positive), the solar cell produces 1.4V at the battery terminals. The NiMH battery was reading about 0.5V ... way low. Will have to see if the battery will charge and the unit start working again.