Method and heating system for heating a fluid line system, particularly in a motor vehicle

A method for heating a fluid line system of a motor vehicle, the fluid line system including a fluid line having a pair of line connectors at ends of the fluid line, the method comprising the steps locating at least two electric heating elements on the fluid line system with one of the heating elements being provided with one of the line connectors and another of the heating elements being provided with the fluid line, electrically connecting and operating the heating elements in parallel and separately supplying each heating element with a controlled operating current for adjusting its heating power, wherein each heating element is separately supplied with its own operating voltage, and each operating voltage is generated from a supply voltage by means of a PWM controller clocked to regulate the heating power with a defined mark-to-space ratio, wherein the respective operating current results from an effective value of the clocked operating voltage and a respective existing resistance of the heating element, wherein successive locations within the heating line system are in fluid communication with each other and subjected to different heating power along the heating line system.