Cars are relying more on electrical components. Wires, harnesses and relays are frustrating to differentiate because of their physical likeness (despite their disparate functions). The main relay in a 1994 Honda Civic electrically controls the fuel pump and fuel injectors. The vehicle has a difficult time functioning when the main relay begins to corrode. The main relay is an integral part of the vehicle and is a difficult part to identify.
Remove the kick panel. It is the lowest removable panel underneath the steering column. Unscrew the three Phillips-head screws.
Locate the fuse box under the steering column. There will be two horizontal columns of multicolored fuse heads sticking out of a panel under the removed kick panel.
Follow, in a straight line with your eyes, the center of the rail of fuses to your left toward the driver's door. Eventually the panel of fuses will stop and there will be a gap of space before the interior paneling starts again. The main relay housing is just beneath this gap of space and butts up to the lower left hand corner of the fuse panel.
Identify the main relay housing. It is a rectangular box firmly secured to the interior paneling by a 10 mm bolt that is oriented toward the driver's seat. It has numerous electrical wires clipped into the bottom of the housing that all feed into a removable plug.
