Donít know how nimble or flexible you are, but if I had this problem Iíd be clearing house in the back and then sitting there while someone sprayed a garden hose from an elevated position (simulating rainfall). And Iíd do it in sections, not like I was washing the whole car at once - otherwise you wonít be sure where the leak is coming from. It may not leak immediately. There may be a delay while something fills up first. So stay in one spot, soak, then wait and listen. Then repeat.
Itís either the back windows or the liftgate window or seal, or the tail lights.
Drilling a hole is a bad idea, but have you even looked yet? There might already be a hole there with a rubber plug. Seems to me Iíve seen this before in one of my old liftgate areas.
2011 Equinox 1LT (new Jan 2011): Summit White / 3.0 L V6 / FWD / Pioneer Stereo / 18" Wheels / 138.2k miles [05-NOV-2019]
2002 Impala 1LT (new Jun 2002): Summit White / 3.4 L V6 / FWD / Cassette-CD Combo /225.5k miles [05-NOV-2019]
Last edited by Colt Hero; 03-11-2018 at 08:29 PM.