Found it earlier this afternoon. Was able to reach up with one hand and disconnect the electrical connection. It isn't one of those *$#^& fittings that needs to be unlocked. It just pulled off. What I did was use in line tap connectors to splice my feed to a relay in my toolbox. Mind you, there's only room for one hand up by the horn and the wires don't have much slack. But I got her done. Now, when I hit my stock horn, my train horn blasts away.