This work aims to plan, prepare and perform a test campaign of the Back-End Electronics(BEE) module in the phasemeter instrument on board the Laser Interferometer Space Antenna(LISA). Results from the test are analyzed to thermally characterize the BEE module as wellto evaluate how successfully an aluminum enclosure mounted on the BEE can dissipate heatloads from the BEE. In addition to the experimental tests, has a computational thermalmodel been developed in COMSOL. The experimental tests were performed in medium vacuum pressure at the Satellite TestEnvironment for Laser Applications (STELA) laboratory at Albert Einstein Institute forGravitational Physics in Hanover, Germany. Steady-state tests show that the aluminumenclosure successfully can dissipate heat-loads of 18.94 [W] from the BEE. Temperatures ofthe BEE would never exceed 55◦ C during testing which is well below the upper temperaturelimit of 75◦ C, thus resulting in a stable thermal environment. Simulations performed of theBEE model also show encouraging results. During time-dependent simulations, temperaturesof critical points from the model would never deviate more than 1.5◦ C from temperaturesof the experimental tests.