Hello, the horn on my clk2 w208 2002 230 is not working. I bought the car a few months back and do not recall it ever working. I popped off the relay cover and checked the fuses 40 and 41 (fanfare), which appear okay. I also listened to the relay whilst someone pressed the horn but heard no sound. I swapped the relay with one in a different car, that was near identical but it too did not work. I read abou the K40 unit often causing problems. I have another problem in that the car feels a bit flat to drive like it is starved of fuel or not getting enough. Another symptom is that the auto changes up such that I could be driving at 30 mph with the engine 1500 rpm. It seems to want to run at much lower revs than what it did. All these problems started a few weeks ago when I was going up and down some quite steep little hills. Any thoughts?

Thanks Frank

For the horn, you will need a wiring diagram. Many modern cars use "CAN bus" , this is a computer communications system where different modules talk to each other rather than having a specific function wire run from place to place.

As for the other problems, you will need to check the usual fuel / air filters , fuel pressure , spark plugs , clogged exhaust, scan the computer for codes.