Automated breakout box for automotive testing

An apparatus for performing a test sequence on a plurality of electrical components of a vehicle of a type having an electronic control module (ECM), the apparatus comprising:

• means for retrieving the test sequence;
• a microcontroller for executing the test sequence;
• means for selectively isolating the ECM from the plurality of electrical connections leading to the plurality of electrical components;
• a current supply comprising:
• a power supply;
• resistance means having a known resistance;
• and
• first multiplexer means responsive to the microcontroller, for selectively routing a current from the power supply through the resistance means and a pair of electrical connections which lead to a selected electrical component of the plurality of electrical components;
• a voltage measuring circuit comprising:
• means for sensing a voltage and providing an output representative of the voltage to the microcontroller;
• and
• second multiplexer means responsive to the microcontroller, for selectively connecting the means for sensing a voltage to sense a first voltage across the resistance means and a second voltage across the pair of electrical connections;
• means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
• means for determining a condition of the selected electrical component based upon the second voltage and the magnitude of the current;
• and
• means for providing an output representative of the condition of the selected electrical component.

An automotive vehicle test apparatus for testing an electrical system of an automotive vehicle, the electrical system including an electronic control module connected to a plurality of electrical components by a plurality of conductors which form an electronic control module bus for carrying electronic signals between the electronic control module and the plurality of electrical components the test apparatus comprising:

• a multipin connector adapted for connecting to the electronic control module bus whereby access to the plurality of conductors is provided to the test apparatus;
• a first multiplexer coupled to the multipin connector for selectively providing a current path between a pair of conductors of the electronic control bus;
• a second multiplexer coupled to the multipin connector and having a pair of outputs selectively connected across a pair of conductors of the electronic control bus;
• means for sensing voltage across the outputs of the second multiplexer and providing a representative digital output;
• and
• controller means for instructing the first multiplexer to provide a current path between a pair of conductors of the electronic control bus, instructing the second multiplexer to connect the pair of outputs to a pair of conductors of the electronic control bus, receiving the digital output from the means for sensing voltage, performing a test based upon the digital output and providing an output based upon results of the test.

A method for performing a test sequence on a plurality of electrical components in a vehicle of a type having an electronic control module, the method comprising;

• retrieving the test sequence;
• isolating the electronic control module from the plurality of electrical components;
• providing a first select signal to a first multiplexer to route a current through a known resistance and a selected component of the plurality of components;
• providing a second select signal to a second multiplexer to sense a first voltage across the known resistance;
• providing a third select signal to the second multiplexer to sense a second voltage across the selected component;
• determining a magnitude of the current based upon the first voltage and the known resistance;
• determining a condition of the selected component based upon the second voltage and the magnitude of the current;
• and
• providing an output representative of the condition of the selected electrical component.

A method for performing a test sequence on a plurality of electrical components in a vehicle of a type having an electronic control module, the method comprising;

• retrieving the test sequence;
• isolating the electronic control module from the plurality of electrical components;
• providing access to a plurality of electrical connections which lead to the electrical components;
• controlling a first multiplexer to route a current through a known resistance and a first set of electrical connections of the plurality of electrical connections;
• controlling a second multiplexer to sense a voltage across a second set of electrical connections of the plurality of electrical connections;
• deriving a quantity representative of cross-talk based upon the first and second sets and the sensed voltage;
• and
• providing an output representative of cross-talk.