Patent ID: 8400328

Claim:
A brake warning device for a tractor and trailer including: a pressure differential sensor; a first pressure sense line connecting the pressure differential sensor to a first air supply line in a tractor spring brake hold off circuit and a second pressure sense line connecting the pressure differential sensor to a trailer air supply line, such that the pressure differential sensor is configured to sense a pressure difference between the first air supply line in the tractor spring brake hold off circuit and the trailer air supply line; and a warning alarm device connected to the pressure differential sensor and configured to warn the user in the event of a negative pressure difference being detected that exceeds a negative pressure difference threshold and to warn the user in the event of a positive pressure difference being detected that exceeds a positive pressure difference threshold; and a bi-directional pressure differential gauge connected to the pressure differential sensor and configured to indicate to a user a pressure difference between the first air supply line and the trailer air supply line over a range of negative and positive pressure differences; and the brake warning device provided in the tractor of the tractor and trailer.