zanc

On removing the 2 fuel pumps from the vehicle I see that one has previously been repaired as it has wires crimped. The second seems to be original and has a black box between the fuel pump and the connector on the fuel tank. The previously replaced fuel pump does not have such a box fitted. Does anyone know what this does? Is it important and should both fuel pump have this black box fitted. Finally, is it possible get hold of new ones?