Thread: Relay Question?
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Old 08-13-2012, 11:53 PM   #5
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Join Date: Sep 2010
Location: Cedar Park, TX
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Re: Relay Question?

Originally Posted by VetteVet View Post
The purpose of a relay is to allow a higher voltage or load to be switched and controlled by a low voltage low draw circuit. This protects switching components such as the headlight switch, electric fans, electric fuel pumps switches, etc. The ignition switch is designed to carry the low amperage draw of the ignition coil so why do you want to put a relay there. If you want to keep the engine running if the switch cuts off you could just put a hidden toggle switch in the coil feed wire and feed it from any hot source off the fuse panel, doing away with the ignition switch altogether as the ignition source.

Having more than the normal voltage to the coil may be necessary if the engine is to be revved more than 6000 RPMs as in drag racing or if you are feeding more than the normal amount of circuits off the ignition switch.
I want to cut the coil power feed with a toggle (for security when I'm away from the truck) but I want to put something like a latching relay in the feed to keep the power to the coil in case the toggle accidentally turns off driving.

So once the ignition and toggle are on it gets power but if the toggle goes off (once it has power) it will continue to have power until the ignition is cut.
Re-starting the neglected '77...
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