I bought my '84 300D last fall and didn't really get a chance to test the a/c before the weather got cool. Already this spring I've had quite a few days warm enough for a/c. I've noticed something strange: when the a/c is on, the horn will not blow properly. Sometimes one note will sound, other times I only hear the "click" of the relay. Once, suspecting that there was a fault with the horn switch, I continued to press the steering wheel hub. The fuse that protects the horn circuit as well as the climate control blew, and then all I got was HOT air! Everything goes back to normal when the a/c is not on. What is the matter here? I'd sure like to be able to drive around in my Benz on a hot day with the windows up and toot my horn at the pretty ladies. Can anyone help? Thanks.