Abstract: An electronic brake controller for controlling electric brakes of a towed vehicle, such as a trailer, wherein the controller includes a resistive braking force sensor that senses the braking force applied by the driver of the towing vehicle to the brake pedal and provides an electrical signal proportional to the braking force to an electronic control unit. The electronic control unit is operable when a microprocessor thereof detects the brake light “on” condition and the presence of the force sensor. The microprocessor receives the signal from the braking force sensor and controls braking force applied to the trailer brakes in proportion to the force applied by the driver of the towing vehicle to the brake pedal. During operation, the microprocessor reads ambient temperature compensated electrical conductance of the braking force sensor to provide a temperature compensated output signal proportional to the braking force to actuate the trailer electric brakes.

Abstract: A pressure relief latching solenoid valve includes one or more axially magnetized permanent magnets disposed proximate a pole piece with the axial magnetization direction of the magnet aligned in a manner to maintain the armature in either the first or second position after the electrical current pulse to the solenoid is terminated so as to provide bistable first and second armature positions that can be maintained without solenoid energization and that can be changed from one position to the other by an electrical current pulse to the solenoid. The armature can control movement of a ball valve of a fluid circuit such that the first and second armature positions correspond to closed and open positions of the ball valve. The closed position provides a maximum fluid pressure in the circuit and the open position provides a preset lower fluid pressure. A spring resides in a passage in the armature and has a preselected spring rate and spring preload.