Relay failure melted down the terminals on this compressor. Many times, the terminals will become brittle and break off. Reconnecting the new relay becomes an artistic challenge at this point. Sometimes, there’s no choice but to replace the compressor for big bucks. This is always true if one of the compressor connection studs breaks off.
So what caused this? A cheesy electrical part, namely the relay, failed because, well, it’s a cheesy electrical part. An unsatisfying answer I know but, without getting into the engineering analysis of material failure, that’s the short answer. And don’t blame the engineers; feast your blood-shot squinties on the bean-counters and marketing geeks hovering over the engineers, hounding them about how the appliance needs to come in at $X in order to meet “corporate projections.”