An active heater control circuit for a deicing heater on a probe mounted on an aircraft, such as a pitot pressure sensing probe, a pitot-static pressure sensing probe, a total air temperature sensor, or engine inlet probe, controls power to the heater through a switch. When activated the switch sends electrical power to the heater until the probe temperature reaches a desired set point. A feature of the invention is an override pulse, which independently activates the switch to provide power to the heater at a selected period and duty cycle such that the aircraft current monitoring circuit receives current sufficiently often to avoid triggering a false heater failure alarm even when the probe temperature has reached its control set point. This feature allows the use of probes incorporating active heat control on existing aircraft configured for older probes having simple nickel-based resistive heater control.