Brake system warning circuit

A warning circuit for a vehicle with an engine and a brake system, the warning circuit actuating a warning device in response to conditions of the brake system, the vehicle having an ignition switch for actuating the engine, the brake system having primary and auxiliary sources of brake actuation fluid pressure and sensor means for sensing the operation of the primary source, the warning circuit comprising:

• a first controlled switch;
• means for coupling the first controlled switch with the ignition switch;
• means for coupling the first controlled switch with a ground potential via a connection through the sensor means;
• a second controlled switch;
• means for coupling the second controlled switch with the first controlled switch;
• and
• means for coupling the second controlled switch with the warning device, the controlled switches cooperating to actuate the warning device in response to an open circuit condition in the connection when the ignition switch is closed.

A warning circuit for a vehicle including an engine, a pressure actuated brake system, and means for actuating the engine;

• said brake system having a primary source of brake actuated pressure, an auxiliary source of brake actuation pressure, a pressure sensor for detecting a failure of the primary source;
• and means for actuating the auxiliary source upon failure of the primary source;
• the warning circuit comprising:
• means, responsive to said actuating means, for generating a warning signal if said pressure sensor indicates said primary source is inoperable and the engine is actuated;
• and
• means, responsive to said actuating means, for generating a warning signal if said pressure sensor is inoperable and the engine is actuated.

A warning circuit for a vehicle including an engine, a pressure actuated brake system, and means for actuating the engine;

• said brake system having a primary source of brake actuation pressure, an auxiliary source of brake actuation pressure, a pressure sensor for detecting a failure of the primary source;
• and means for actuating the auxiliary source upon failure of the primary source;
• the warning circuit comprising:
• means, responsive to said actuating means, for generating a warning signal if said pressure sensor is inoperable and the engine is actuated.

A warning circuit for a vehicle including an engine, a pressure actuated brake system, and means for actuating the engine;

• said brake system having a primary source of brake actuation pressure, an auxiliary source of brake actuation pressure, a pressure sensor for detecting a failure of the primary source;
• and means for actuating the auxiliary source upon failure of the primary source;
• the warning circuit comprising:
• means, responsive to said actuating means, for generating a warning signal if said auxiliary source actuation means is inoperable and the engine is actuated.

A warning circuit for a vehicle including an engine, a pressure actuated brake system, and means for actuating the engine;

• said brake system having a primary source of brake actuated pressure, an auxiliary source of brake actuation pressure, a pressure sensor for detecting a failure of the primary source;
• and means for actuating the auxiliary source upon failure of the primary source;
• the warning circuit comprising:
• means, responsive to said actuating means, for generating a warning signal if said pressure sensor indicates said primary source is inoperable and the engine is actuated;
• and
• means, responsive to said actuating means, for generating a warning signal if said auxiliary source actuation means is inoperable and the engine is actuated.