CarFusebox

Fuse Relay Ignition Switch Wiring Details With Diagrams Fuse Panel, Ignition Switches, Etc... How to Wire Stuff Up Under the Dash. How do you wire up the fuse panel? What do you need to do to the dash? How's the ingition switch fit into all this? First you have to figure out what you've got to work with. Are you using an original ignition switch? Is it from an older car? Or are you starting from scratch and have a new universal ignition switch? If you still want to run the original switch, it's probably not capable of carrying enough current for modern needs without seriously limiting the the voltage or burning out all together. However, there is a way to keep it and still use it to power everything.  That's right, our old friend the relay. The relay is just an industrial sized switch. With it the older ignition switch can still be used, but now it will simply turn on and off the relay which takes hardly any juice at all... And it's simple to do: ...