That week in February when three squawks turned into one gremlin wire

Had one of those weeks last month where every plane I touched came back with the same squawk two days later. Monday I chased a intermittent APU fire loop fault on a 737, pulled and swapped the loop card, ops check good, signed it off. Wednesday it comes back with a fire loop fault on the other side. Thursday I find it, a chafed wire behind the aft galley panel rubbing on a bracket that only grounds out when the cabin flexes in cold soak. Spent about 6 hours total over three days on what turned out to be one 30 cent piece of loom. The thing that bugs me is the first two cards I swapped tested good on the bench, so I made a liar out of myself twice. How do you guys handle intermittent squawks on stuff that only shows up in flight, do you just bite the bullet and start wiggling every harness or is there a smarter way?