How do I control the height on 2017 so not to hit the top of garage

 

You don't, at least not when you're letting the hatch open automatically. Unlike some suvs and crossovers, there's no liftgate height setting on the RDX. Prior to purchasing ours, my wife and I actually drove an RDX home from the dealership to be certain the hatch would miss the garage top. It does, by about 3/4 inch (whew!). You could try opening it manually (hold the liftgate button a couple of seconds, you'll hear a couple of beeps then can lift the gate yourself. Failing that, you might have to adjust your habits and only open the rear when you're not in the garage.

Cheers!