Control system for an electric heating unit fitted in a motor vehicle equipped with a powertrain comprising at least one electric motor connected to an electric battery, the electric heating unit being powered by the battery comprising a heat-transfer fluid circuit, characterized in that it comprises a means for limiting the power consumed by the electric heating unit and a temperature regulating means, cooperating in order to transmit a control signal as a function of a measurement of temperature of the heat-transfer fluid of the electric heating unit, and of a temperature setpoint for the heat-transfer fluid of the electric heating unit, the power limiting means being able to determine a limiting of the control signal as a function of a measurement of power of the electric heating unit and of an authorized power level for the electric heating unit, said system being characterized in that: either the power limiting means comprises a mapping of the control signal as a function of the power of the electric heating unit, and an amplifier able to modify the signal transmitted to the mapping unit as a function of the power of the electric heating unit and of the power of the electric heating unit used to set up the mapping, or the power limiting means comprises PID control, a first input carrying a measurement of power of the electric heating unit, a second input carrying an authorized power level for the electric heating unit, the system comprising a controlled amplifier connected at its input to the second input and at its output to a mapping unit, the mapping unit being connected at its output to a switched input of a switch, another input of the switch being connected to the output of the power limiting means, a branch off the connection at the output of the switch is connected to an input of a comparison means, the comparison means being connected at its input to memories (91, 93, 95) and to a reprogrammable memory via a bidirectional connection, the memories (91, 93, 95) comprising a first threshold, a second threshold greater than the first threshold and a threshold duration, the reprogrammable memory comprising a stored power value, the comparison means being connected at its output to the control terminal of the amplifier and to the control terminal of the switch, the comparison means being able to transmit a gain value to the amplifier and a logic value to the switch as a function of the comparison of the signal transmitted by the output with the threshold values stored in memories (91, 93), the switch being able to transmit at its output the value received from the power limiting means or the value received from the mapping unit as a function of the received logic value, so as to provide economy in the computing of the power limiting means when a non-zero gain value is transmitted by the comparison means to the amplifier. either the power limiting means comprises a mapping of the control signal as a function of the power of the electric heating unit, and an amplifier able to modify the signal transmitted to the mapping unit as a function of the power of the electric heating unit and of the power of the electric heating unit used to set up the mapping, or the power limiting means comprises PID control, a first input carrying a measurement of power of the electric heating unit, a second input carrying an authorized power level for the electric heating unit, the system comprising a controlled amplifier connected at its input to the second input and at its output to a mapping unit, the mapping unit being connected at its output to a switched input of a switch, another input of the switch being connected to the output of the power limiting means, a branch off the connection at the output of the switch is connected to an input of a comparison means, the comparison means being connected at its input to memories (91, 93, 95) and to a reprogrammable memory via a bidirectional connection, the memories (91, 93, 95) comprising a first threshold, a second threshold greater than the first threshold and a threshold duration, the reprogrammable memory comprising a stored power value, the comparison means being connected at its output to the control terminal of the amplifier and to the control terminal of the switch, the comparison means being able to transmit a gain value to the amplifier and a logic value to the switch as a function of the comparison of the signal transmitted by the output with the threshold values stored in memories (91, 93), the switch being able to transmit at its output the value received from the power limiting means or the value received from the mapping unit as a function of the received logic value, so as to provide economy in the computing of the power limiting means when a non-zero gain value is transmitted by the comparison means to the amplifier.