Gremlins in a simple horn circuit?????????

mikeh77586 · #1 (**permalink**) 06-08-2011

OK, I've been humbled. I have been working with electric - electronic circuits for over thirty years but have never had so many problems wiring a simple horn circuit. I am attempting to install a horn on my sailboat. It is an AFI miniblast 12v w/3 amp draw. It calls for a minimum wire size of #16. I happened to have some 2 con # 16 so I installed the wire, connected my horn and nothing. It didn't work. So I figured larger wire size, less resistance, better connections. I pulled the # 16 and installed #12. Still doesn't work. So I pulled the Horn and brought it back to the battery & touched the leads on the horn directly to the battery and it works. After that, I got the continuety tester and checked all conductors, connections, push button and everything checks ok. Re-connected and still nothing. I am at a complete loss as to what is wrong. The distance on wire from the battery to the horn is 25 feet. I wouldn't think of that at a 25' distance a voltage drop could occurr that would cause the horn not to operate. But then again, I know the circuit is making but it isn't making the horn solinoid kick and the horn to sound. Any suggestions??????

Thanks for your help!!!!!!!

Maine Sail · #2 (**permalink**) 06-08-2011

Mike,

The electrical distance is 50' or 25' each way. At 3 amps for a 5% volrage drop you'd need 14GA and for a 5% VD you'd need 12GA.

If all the wires test out fine, continuity wise, the switch is fine, and the horn works when connected to the battery it is either a VD issue or a termination issue.

Make sure your horn circuit is getting 12V power and negative is connected to the 12V DC system. I know this sounds obvious but the ground is often overlooked..

mikeh77586 · #3 (**permalink**) 06-08-2011

I'm going to change the location from the edge of the forward bow to just infront of the mast. That will cut 12 feet from the distance and hopefully should correct for the VD. Thanks for the post. I wasn't figuring the return trip from device. Which would of course make it a 50' run and not a 25"

Thanks...

Mike