93 chevy Blazer 4.3 'W'

I keep getting Code 43 - I changed the left side Knock sensor - Easy- Now the light doesn't come on as much so I assume if a change the other one it will clear up-
Where is the second Knock sensor ? I belive it's behind the right cylinder head - What do you have to do to see it/get at it ? Any ideas - I imagine the thing is gonna be stuck - Thanks:smile:

Nobody has ever taken one out ? :screwy: