The fuel fired vehicle heater has a starting sequence initiated when the ignition key (7) is operated. Temperature sensors in the heat exchanger (4), inside the vehicle (12) and outside the vehicle (13) are linked to the controller which regulates the heater. The heating action is blocked when the temperature of the heat exchanger is above a set level. The heating action is also inhibited when the electric starter is operated. This is controlled by the battery voltage dropping below a set level. The heating can also be controlled by the voltage output from the generator (3).
