This paper investigates the efficiency of PID and Fuzzy Logic Control approaches as a voltage control method in vehicles with 48V E/E architecture. Then compares the mentioned methods output on Buck converter for 48V to 12V. Buck converter aims to convert 48V to 12V to be able to supply power to low voltage systems such as electric power steering systems within vehicles. 48V E/E architecture is becoming a common architecture among electric vehicles and power distribution through 48V batteries, hence it is chosen for this study. Our study presents that Fuzzy Logic Controller has a better performance in terms of response time and settling time on controlling output voltage of Buck converter which converts 48V to 12V.