Mel, the 230 is a bit different. There are two different contact rings used on the 230 models, but there is no set of contact brushes/carbon piles like the late 250 and 280 models use. Both versions of the 230SL contact rings are adjustable. In the pictures below you can see the three screws on the early version, and the one screw on the later version. If these are too tight or loose this can cause the horns to sound when turning the wheel. If the springs inside of them have weakened or broken that will also cause the horns to sound when turning the wheel.
The loose horn ring....they were supposed to be tensioned by a spring that was compressed between the inner race of the steering wheel shaft bearing and the rear bracket that the horn ring was attached to with the chrome acorn nuts. However, I've seen some later 230 models that didn't have this spring and relied on the spring tensioned contact ring to keep the horn ring taught. I'll have to rely on someone else to comment further on this aspect of things. I just don't remember enough, and I'd hate to mislead you. Regardless, I still think that your issue will have something to do with the contact ring.
