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, comprising:

• a first electro-pneumatic brake control valve configured for mounting on the first towed member and configured to output fluid pressure from a fluid source received at a supply port on the first electro-pneumatic brake control valve through a first delivery port on the first electro-pneumatic brake control valve responsive to an electronic control signal that is generated by a brake controller on the towing member;
• and,
• a double check valve having a first supply port in fluid communication with a forward fluid coupling on the first towed member that is configured to deliver a first fluid control signal from the towing member to the first towed member, a second supply port configured for fluid communication with the first delivery port of the first electro-pneumatic brake control valve and a delivery port in fluid communication with a rear fluid coupling on the first towed member and configured to deliver a second fluid control signal from the double check valve on the first towed member to the second towed member.