A heavy vehicle trailer antilock braking system module includes a module control port receiving a pressure signal, a module exhaust port fluidly communicating with atmosphere, a first switching valve, a second switching valve, a relay valve, and control logic. The first switching valve includes an input port and an output port. The first switching valve input port fluidly communicates with the module control port. The second switching valve includes an input port and an output port. The second switching valve output port fluidly communicates with the module exhaust port. A relay valve includes a supply port, a delivery port, an exhaust port, and a control port. The relay valve control port fluidly communicates with the first switching valve output port and the second switching valve input port. The delivery port fluidly communicates with the supply port and the exhaust port as a function of a pressure signal at the relay valve control port. Control logic causes the second switching valve input port to fluidly communicate with the second switching valve output port for a predetermined time after electrical power is no longer supplied to a vehicle service brake stop lamp.