The 2005 Ford Escape Hybrid is basically an electric car with a gasoline engine back up. This car is powered by Ford Duratec 2.3L 4-cylinder gasoline engine matched up with a 70KW (equivalent to 94hp) permanent magnet traction motor. The electric motor can propel the car on its own or in concert with gasoline engine to provide performance equivalent to a conventional V-6.
The Ford Escape hybrid uses a serial interlock type system. In this system, each cable/wire that carries high voltage has an interlock circuit that reports the status to the battery pack controller via two discrete (dedicated) wires. The basic Escape hybrid high voltage interlock circuit can be in the following file. In this design if the serial interlock circuit is broken/opened (intentionally or unintentionally) the battery pack controller will sense the circuit status change and command the high voltage contactors/relays open so that, the high voltage bus capacitors can be discharged, and render the circuit to a safe condition. (source: autoresearchanddesign.com)