1044993
Bucklahoo, A relay is nothing more that a remote switch. It has a coil that, when energized by 12vdc, the coil pulls a connector (switch) closed,(Normally open) and at the same time Opens a contact (for normally closed) The contacts on the switch part of the relay are rated pretty high for current, usually 30A. Where some switches are rated under that. The relay allows you to control high amperage circuits with very little current (whatever the coil may draw, 60 to 90ma maybe ) The relay coils can be energized by anything that supplies 12vdc, like for instance, the back-up light wire. When you shift into rev. the transmission switch closes and sends 12vdc back to the back-up lights. That 12vdc line can "energize the relay, thus turning on bigger back-up lights.
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