Thanks to people in here, I am coming aware of this great invention. Mine is programmed 3 ways.....COAST..LATCH..MANUAL= For COAST AND LATCH Cruise Control switch ON position, but not activated. COAST activates the Exhaust Brake when I touch Service Brake. Let up on Service Brake and Exhaust Brake temporarily goes off until I touch Service again LATCH activates the Exhaust Brake when I touch Service Brake. Let up on Service Brake and Exhaust Brake remains on until I touch throttle pedal. MANUEL...If throttle is released the Exhaust Brake activates as normal. Just thought ??? Does the brake lights LIGHT when tghe exhaust brake is ON?