I have ran into a problem with a large system we installed about five years ago. Last fall, two zones started to come on simultaneously. I have isolated the problem to the point that I know that the two control wires are either making contact out in the field or they are going to ground out in the field. The wire is 18 guage multi-strand with 13 conductors. There was a lightning strike about a month or so before this condition appeared. Is there an efficient way to find out where the two wires are making contact?