If it's the corrugated plastic tubing (which you'd only be able to tell by removing an A-pillar handle) then you're unlikely to be able to split it. This is a terrible type of tubing to use for a drain as the edges inside just collect gunk a lot faster than a smooth-walled tube would.
I did the TSB reset, which involves pulling the fuse and it seems to have helped the top make a better seal. But I've still not gotten the front drains blown clear, as I don't have the right fitting to get down to the holes. One... more.. tool... to buy...