"Cold Junction"? Is that a bad solder connection? If it is the usual technical English would be "Dry Joint". Strictly speaking that's for a joint which was never properly wetted by the solder when it was made, but in common use it's any soldered joint which has failed.
"Cold Junction" specifically in technical English is the term for one of the two junctions in a thermocouple pair. The other one is not surprisingly the "Hot Junction". Of course there's confusion possible there too- the reference junction is normally referred to as the cold junction, so it's entirely possible for the hot junction used for measuring the temperature to be colder than the cold junction
