This document presents a method for detecting single hard faults in linear analog circuits using a simulation before testing approach. The method generates test vectors for nominal and tolerance-bound component values to form a fault dictionary. The circuit under test is then simulated with injected faults. Fault variables are derived by comparing nominal and faulty responses. The component with the lowest relative standard deviation of its fault variable is identified as faulty. The method was tested on benchmark circuits like a linear voltage divider and correctly identified injected short and open faults in components. The technique addresses tolerance challenges in analog circuit testing.