Horn Relay

[suzukizone]

Actually for my '81 GS 850 but eventually for the 500.  I want to install a horn relay to insure horns get full voltage & loudest sound.  Relays I find are triggered by a lead supplying 12V positive.  The horn button, however, is supplying ground & would not trigger the relay. Does someone know where I could get a relay that is triggered by grounding such as the horn button will do?
Thanks
DH

[Chuck]

Relays are triggered by a DC current, which is one positive lead, and one ground lead.  You can put a switch on either lead.  Splice an on-with-key postive wire from the wiring harness, and take your negative from the horn button and it will work.

I'm not trying to be mean, but also buy some fuses because it sounds like you're not too sure what you're doing.

Are you using some aftermarket high-current horn that's giving you a problem with the stock switch?  Because if you're just being paranoid, I'd just forget about the added complexity.  The stock horn switch will probably work just fine with anything you give it.

[LimaXray]

A relay isn't going to make any difference.  There aren't relays trigger by 12v and relays triggered by ground, all relays work the same way.  I'm going to avoid going into explaining the simple circuit and sum it up as this: for a relay to be triggered, it needs both 12v and ground.  If you really want to use a relay, connect the relay's coil to the same wires the horn is connected to now.  Take a wire from the (+) of the battery to the normally-open terminal on the relay, the a wire from the common terminal on the relay to the (+) terminal on the horn, and finally take the (-) terminal on the horn to ground.   This would be totally pointless with the stock horn, but would be needed if you wanted to use a big air horn or something

chuck beat me to it