Service Brake Control System for a Combination Vehicle

A service brake control system for a combination vehicle including a towing member and first and second towed members includes an electro-pneumatic brake control valve on the first towed member that delivers fluid pressure through a delivery port in response to an electronic control signal that is generated by a brake controller on the towing member. A double check valve includes a first supply port in fluid communication with a forward fluid coupling on the first towed member that delivers a first fluid control signal from the towing member, a second supply port in fluid communication with the delivery port of the electro-pneumatic brake control valve and a delivery port in fluid communication with a rear fluid coupling on the first towed member that delivers a second fluid control signal from the double check valve to the second towed member.