Thanks for the advice, guys. I'll keep 'er at 12 volts and take it easy on blowing it. The horn wasn't hooked up when I got the truck, so I don't know what it sounded like at 6 volts. But it is plenty loud now. Also got a spare horn just in case. And the resistors I tried were new, but never tested so maybe they're bad. I'll check 'em out later.
