An extensive experimental investigation of the forced convection cooling process of electronic equipment with metal substrates used in automobile industry is described. The study is motivated by the desire to predict the heat transfer coefficient of a heated electronic device with complex geometry. Most of the previous investigations of heat sinks have been dealt with different heat sink geometry when the components are located on isolated surfaces or within channels formed by two parallel planes. Thermal conductivity of various sink materials used leads to the different cooling situations. Besides, the forced convection heat transfer is affected by the rate and propagation of the cooling air or gas flow. The wide range of the flow velocities or Reynolds numbers, two shapes of the heat sinks and their specific material make this study an important one. The details of the mathematical model used for the analysis of the experimental data obtained are presented. These include the final Equation for the heat transfer coefficient as well as the procedure of the results transformation. Results and their comparisons with the data of the other authors are discussed.