Main Relay (Computer/Fuel System): Description and Operation

PURPOSE
The main relay provides battery power (B+) to the engine control module (ECM).

OPERATION

EFI Main Relay Circuit Schematic:

Refer to the included image for circuit components.
Power from the ignition switch in the ON position comes into the main relay at pin # 1, energizes the coil and grounds from pin # 2. The activated coil closes the contacts allowing power to flow from the MAIN FL 2.0L, through the 15 amp EFI fuse, through the Main relay and to the B+ terminal of the engine control module.