Getting ready to pull the front bumper cover, clean the radiators and maybe install mesh over the intakes.While I have it off I want to check the horns as they are not working.  I have checked fuses and changed the relay ( I think I changed the correct one, but not sure.  Mine is an 04 boxster S and the schematic I saw was a 2000 or 2001 ) but no luck.  I don't hear a relay clicking when I try the horn.  Anyone know of a step by step check list to isolate the problem?  thanks  mountainman