Abstract: The embodiments herein relate to a method in a first unit for determining location of deteriorating hardware. The first unit obtains information indicating a first signal level of a first signal and a second signal level of a second signal transmitted over a wired communication link and over a period of time. The first unit monitors the first signal level and the second signal level over the period of time. When a deviation in the monitored signal levels has been detected, the first unit determines a location of the deteriorating hardware by comparing the deviation in monitored signal levels to known signal deviations for various locations of the deteriorating hardware. The location is in at least one of the wired communication link, the second unit and the third unit.