Okay, as promised, I will post a few pics on how to remove the rear door panel on a 2015 Equinox LTZ. It should be similar to the 2010 - 2014 Terrain and Equinox as well. I am posting it here to augment the excellent thread BowtieMan has already started. Excellent video by the way BTMan! EDIT: This is not the complete set of pictures. I will post another set showing the inner door cable removal and some other things For now, read the text on how to remove the door lever cable.
Again, you need to use a plastic removal tool or other flat non marring tool, to start to pry the lower rear corner of the door open enough to get you fingers behind the edge of the inner door panel. Then I placed my knee against the bottom edge of the outer door and PULLED firmly but gently. Once the first of the 10(?) plastic inner retainers pops loose, the rest come pretty easy. Some may pop out of their seats inside the panel or even remain in the holes inside the door, which you will have to reinstall in the door panel slots before replacing the inner door panel. NOTE: Do not try and use the plastic removal tool to pry the door panel off. I doubt is would survive. Use the tool to only open the edge of the panel enough to get your fingers behind it.
Once the panel is loose, or before you pry it loose
, you also need to remove an 8mm hex head screw under a small plastic panel behind the door opener lever and TWO 10mm hex head screws under the door pull well/power window switch assembly. That little plastic panel has a small lip on it's lower rear corner. You can use a bent paper clip, small screw drive or even your finger if it fits, to catch the lip and pop the panel off. Remove the 10mm hex head screw behind it.
Then you need to remove the entire "pull well - Power window switch assembly. This is accomplished by using a small plastic pry tool inserted into the rear most edge of the door pull well. Use care when doing this and pull in firmly to start to release the steel spring clip that holds the assembly in place. Take care and watch that you do not start to pull out the vinyl fabric cover of the inner door panel. Once the door pull well is out, the electrical connector to the power window switch is removed by finding the usual "squeeze" clip on the connector, depress it, and pull the connector out of the switch. Then find and remove the two 10mm hex head screws that are now visible.
After, the 8mm and TWO 10mm screws are removed, the panel is removed by pulling it upward to release it from the spring metal clips just below the window. Take care now NOT to bend the manual door lock plunger linkage. Once the panel is unclipped and apart from the door, you must remove the door level cable from the lever. There is a small blue plastic clip that surrounds the end of the door opener cable and holds it in place. If you look closely, you will see it has a little "latch" on the end of it. Pull up on the latch gently with a finger nail or small screw driver just enough to unhook it. Then, you can pull the whole cable out (rearward) a bit. Now, simply move the whole cable outwards (sideways) and free from where is was. If you look closely, there is a slot in the cable end holder that allows you to slip the cable into or out of the cable end attachment point.
I needed to do this to install a pair of Rockford Fosgate 6 3/4" speakers. These are 4 ohm speakers and work quite nicely to improve the overall balance of sound on the factory Pioneer head unit. They do not have the "tubby" bass of the original rear Pioneer(?) speakers and have a nice extended and clear high end. They really fill in the whole sound stage and I can now balance out more towards the front Pioneer speakers, which I am leaving in, since they have fairly decent sound and bass output for their size. Also, as some may know, setting the balance a bit more towards the front speakers also drives the rear sub woofer with a bit more signal so that also improves output in the low end.
I know some say or think the Pioneer system in the Equinox-Terrain isn't that great, but with the replacement of the rear door speakers using a 4 ohm 2-way coax speaker of 90db sensitivity or so, I find the system performs quite well. Far from a custom system, but still nice full sound and a surprising good thump of bass when you balance the Frt/Rear about 20% more towards the front speakers and have replaced the rears with some 4 ohm speakers that give a bit more high end and low end clairity and defintion.