rear Shimano brifter not shifting
I have a 5 month old Bike, Redline Conquest Classic, quite happy with it. This morning, the right (rear) brifter started acting up, it will pull the chain up to larger cassette cogs, but doesn't want to reliably drop the chain back to the smaller cogs.
It's a Tiagra 9spd brifter, so the "inside" paddle nearest the bars is the one that's not working.
Anyone have any ideas what's wrong? I'm guessing it's a busted spring or ratchet or something, but I've never taken one of these apart, and from what I hear, it's not a good idea to do that anyway.