This paper details an investigation, through an experimental study, of the development of weld nuggets and a heat-affected zone (HAZ) in resistance seam welding (RSEW) using a numerical simulation approach. SYSWELD software for the simulation of heat treatment, welding, and welding assembly was utilized for the simulation process. The integrated Spot Weld Advisor (SWA) in SYSWELD was applied to simulate the RSEW model using a two-dimensional axis-symmetric FE model with customized electrode meshing. The thermal-mechanical-electrical characteristic and contact condition were taken into account throughout this study. The developed model comprised a transverse cross section for welding two layers of low carbon steel with a thickness of 1 mm. For the experimental verification, three-pulsed RSEW with two different current stages was carried out. It was discovered that this program code, Spotweld Advisor, when used with the meshing method, was capable of offering results that were in agreement with physical experiments.