control system of a thermal regulation means of a cooling circuit of an engine of a motor vehicle and control of said control system METHOD

A control system for a thermal regulation means (8) of a cooling fluid circulating in a cooling circuit (2) of an internal combustion engine (3) of a motor vehicle, said temperature control means of the fluid comprising a fluid inlet (8a) connected to a cooling fluid inlet at the output of the motor (3) and a first, second and third fluid outlets (8b, 8c, 8d) connected respectively to a first branch (2a) containing a radiator (5) engine coolant, a second branch (2b) containing a working fluid exchanger-oil (7) and a third branch (2c) containing a heater (6). The control system comprises a module (13) for determining the operating mode in summer or winter mode the heat regulation means and a module (16) for controlling the opening or closing of the third part (2c) as a function temperature (T_fm) of the fluid leaving the engine and the temperature (T_FA) of fluid upstream of the heater.