A refrigerant leak detection system is provided for a motor vehicle, in which the system includes a heating, ventilating, and air conditioning (HVAC) module having a refrigerant sensor assembly adapted to be fixed within the drain hole of the sump. The refrigerant sensor assembly includes an elongated sensor element extending into the sump, a flange portion having apertures that allows the condensate to drain from sump, a collar portion with self-tapping threads.