Several of our sites have been in operation for 20 years or more and we are starting to see the effects of connector exposure to the elements, mainly reliable contacts, especially if any moisture or high humidity conditions exist. Some suggestions to manage this issue are:
Exercise each circuit board connector several times to scratch away and re-expose bare metal to both sides of the contacts. A good dielectric grease on the pins may alleviate future corrosion.
Any conduit or cable runs entering a box from the top need to be examined closely since the condensation of summer humidity in the winter will accumulate in the housing and cause electrical issues as well as corrosion. Visually look for gray scum, green discoloration, or rust when opening any housing.