The reliability of electronic assemblies remains a critical concern in modern industrial applications, especially as components are increasingly exposed to combined mechanical and thermal stresses. In particular, board level interconnects - as for example Ball Grid Array (BGA) solder joints - represent one of the most failure-prone elements in microelectronic packages, yet their health assessment during ageing is still not fully understood. This work investigates the degradation mechanisms of BGA solder joints through an accelerated life test combining high-temperature exposure at 125°C and repeated mechanical shocks with 120 g peak magnitude. Custom-designed test boards were developed to monitor specified groups of solder joints located in different regions of the package, both near the chip corners and in more centered positions. This is done to evaluate the spatial dependence of stress effects during the ageing test. A four-wire resistance measurement method has been implemented to continuously monitor the electrical behavior of each solder joint structure throughout the test. Variations in the measured resistance enabled the identification of distinct operating zones, including stable (i.e., healthy) behavior, pre-failure conditions, and actual failure. The experimental results demonstrate clear correlations between stress location and degradation trends, highlighting the effectiveness of resistance-based health indicators for real-time diagnostics. The outcomes of this study provide new insights into BGA reliability under combined stress conditions and support the development of prognostic tools for the health management of microelectronic assemblies.