What is the best way to do this? I keep reading the word “relay” when I google this question, but am not quite sure what that is.
I saw a video that used a “add a fuse”, where you plug this fuse that has a wire connected to it into an empty spot on your fuse box, and you crimp the positive wire of your accessory onto he wire connected to you "
add a fuse". I’ve also read that a horn should typically use a 15 amp fuse… (The horn has one small positive wire coming out of it. It will be ground to the car when I bolt it onto something steel under the hood.)
Can it really be that simple!? This add a fuse thing sounds great. But will it work properl;y for a horn? And what about a relay? Do I need it?
It depends on how you want the horn to work. If you want the horn to be on a seperate switch from the regular horn, then it’s just a matter on running a seperate circuit with the proper size wire, fuse, and switch that can handle the current draw of the horn. If you want the horn to operate off the horn circuit of the car with the regular horns, that’s going to be a little more complicated.
The last time I installed a separate horn I had it operate off a separate pushbutton switch mounted atop the steering column. Then I powered the accessory off the wire to the cigarette lighter without inserting a separate fuse, since I would not operate both accessories at the same time. (Hmm… Now times have changed. Many people leave a GPS or a charger constantly operating off their 12v outlet.) Or you can tap off the power window or door lock circuit if you wish.
If you wish to add a separate fuse, you can use an inline fuse for convenience rather than adding to the fuse box.