One problem related to underhood wiring has been reported for the 1997 BMW 740. The most recently reported issues are listed below.
Car was running fine, was at a stop light and the car shut off had a really strong electrical smell coming from the engine compartment. Opened up the hood and had a flame down at the thermostat area. Quickly put it out and pushed the car off to the side of the road. Had to have a tow truck come tow the car and bring my family out of the freezing cold as well. The thermostat and wiring from the ecu down to the thermostat had to be replaced as well as a fuse that had blown in the main engine harness. Old part was disposed of as well as the wiring.