A controller for a vehicular power accessory includes an elongate sensor electrode (102), a capacitive shield (104) extending significantly beyond the sensor electrode (102). A dielectric (106) is disposed between the capacitive shield (104) and the sensor electrode (102) to isolate the sensor electrode (102) from the capacitive shield (104). A sensor processor (114) is in electrical communication with the sensor electrode (102) for processing sense data received from the sensor electrode (102). A power actuator (202) is in electrical communication with the sensor processor (114) for effecting movement of the power accessory in accordance with the processed sense data. The sensor electrode (102) can be applied to various vehicle locations with the purpose of detecting obstacles and activating an alarm or display.