Pushbutton Back-up Switch

1962 Valiant pushbutton auto, has factory reverse lights, fuse/wiring is good, has power to the switch, can jump it to the other side and reverse lights will come on.

Switch is in pic under pushbutton assembly, white wires are soldered to it.

Checked for a back-up switch, none listed. Are these unavailable?

Is there a solution other than installing a manual toggle switch?

Also, anyone have a part# for the horn relay?

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