help with manbearpig

How do you attach the sensor to the electric transformer in the meth lab next to Kenny's house? When I go in the ladder to the roof isnt climbable as its blocked by some sparkling wall which you cant shoot, how do you get past this?

You either break it by hitting it, if that's not possible then look for a way to explode it by farting. Is there a fire nearby?

Just hit the wall with a melee attack and it will break, allowing you to climb up.