Method for controlling a HVAC system in a vehicular compartment includes monitoring temperature of an occupant in the compartment from a location apart from the occupant, and controlling the HVAC system based on the monitored temperature. The primary unit includes a damper tube, a spring chamber, and a piston rod that supports a main piston. The inlet mouth is fluidically connected to the compartment to supply it with the fuel in order to lubricate andor cool the pump itself.