For some reason, when I locked the car yesterday via remote, the pathetic little alarm horn didn't homk. This has happened to me only once before, and I have the strange feeling it's somehow related to my aftermarket radio. reason I think so is that the only other time it happened was when I had partially disconnected the OEM radio. But my current HU works fine and this is the first time it's happened. What's the deal? Doors lock fine, just no "puhhht."