Power electronics addresses an ever-growing market with challenges in many fields as in transportation and aerospace. Power electronic conversion is one of the most appropriate way to reduce weight and volume in systems, especially in severe environment like in aeronautics. Power converters are modular and basically constituted of power semiconductor modules. It is well-known that the reliability of the whole system is strongly affected by the power module performances. In the perspective of achieving high reliability power converters, the online condition monitoring (CM) is a promising approach to detect aging and failure issues in power modules. This article proposes to investigate the role of a passive sensor, i.e. a strain gauge, to be considered in the design of planar power module (without bonding) based on Silicon Carbide (SiC) MOSFETs. The sensor is combining electrical, thermal and mechanical health indicators. After an analysis of failure modes expected in a lab-scale power module, an experimental test bench for measuring such indicators is introduced. Signatures of failures are analyzed in accordance with failure occurrences. Particularly, initial results using a strain gauge are discussed and compared to other sensor responses (especially based on VdsON, voltage between the drain and the source of the transistor when conducting). Promising results are established as well as limitations and future work.