<p>This paper presents methods for determining the fatigue failure analysis of dissimilar welded joints by applying automatic opening doors in city buses. The paper focuses on the problem of determining and evaluating the fatigue life of selected types of welded joints by the application. The study shows the extent to which the simplest method based on the amplitude of nominal stress can be used for calculating fatigue life based on two selected types of joints with different asymmetry coefficients, R =  − 1. Three groups of welded models, MS-SS, SS-GI, and MS-GI specimens were designed according to ASTM E466 standard. The FEM model is developed for dissimilar metal welded joints. The present study aims to experimentally investigate the high cycle fatigue strength of dissimilar welded joints subjected to tension–compression loading and Full capacity uniaxial fatigue machine with load 40% YS for MS-SS, MS-GI, and SS-GI dissimilar welded joint conducted. Numerical model developed in high cycle fatigue failure for dissimilar welded joint subjected tension–compression. The numerical results of the welded joint model have been validated with available literature. It shows that the present mathematical model agrees with Shigley &amp; Mischke (<CitationRef CitationID="CR12">2004</CitationRef>). Also, parametric studied the effect on fatigue strength by changing: the welded length and welded thickness. The fatigue failure of dissimilar load cycles has been recorded for different models, MS-SS = 230,830 cycle, MS-GI = 166,362 cycle, and SS-GI = 173,867 cycle respectively. The SEM and EBSD observations in the distinct microstructural features, depending on the extent of mixing of both base metals.</p>