The wiring for the horn and lights is fed through the support brackets and down between the shell and matrix. The cable is held in place by the two metal straps shown at 'A' and 'B'.
The upper strap, 'A', is attached by the lower set screws for the support bracket. Care is needed, when installing the matrix , as it is easy to loop the cables under the bottom tank which stops the radiator seating properly in the shell.