I also had the digitizer for my 2010 Trail edition go bad. The top half of the display would register touches, but the bottom half would not. After getting into the *maintenance mode to view the touchpoints, it looked as if the touches on the bottom half of the screen were all registering on the very bottom of the display.
The stereo is a JBL E2029 printed on the lower part of the face. I ordered the standard 8" digitizer screen for the E2022 Prius since the seller said it would work on the 4Runner. I paid $25 for it on eBay. I looked at a few videos and installed it without any issues. Note: all of the ribbon cables have locking mechanisms that need to opened prior to removing the ribbon cables. The one on the main unit pulls out towards you. The one that separates the metal back piece has a metal back that lifts up. The one for the digitizer is another one that slides out toward the ribbon cable.
Unfortunately, when I tested it the new digitizer, the touchpoints appeared random. They would not appear where my finger was touching. I uninstalled it, checked all of the ribbon cables and put it back in. Same thing. Inaccurate random touchpoints. I also didn't love that the new screen was shiny glass and would show fingerprints easily.
I removed everything for a 3rd time and just decided to clean up my old digitizer and put it back in so that at least the stereo would work while I wait for a replacement. To my surprise, the old digitizer is working again perfectly! All touchpoints are accurate and work even with the lightest touch.
Diagnostic Mode from BlackWorksInc
https://www.toyota-4runner.org/2170887-post2.html
-Ignition "Key On," not Accessory (Engine Running or Not, it does not matter)
-Press and Hold the "Info" (on some head units it will be the "Apps" button)
-While Holding the "Info" (or "Apps" if equipped) button, cycle the headlight switch from "Off" to "On" 3 Times (Off -> On -> Off -> On -> Off -> On -> Off)
The head unit should enter a very simple looking interface with some options (if not repeat the process again), select "Function Check/Setting" from the menu. Once you've entered that sub-menu you should see "TouchScreen Switch," select that and it will bring you to a testing screen. Press anywhere on the touchscreen, there should be a " + " symbol where the touchscreen registered your touch (this symbol will stay in place until you touch the screen again); this will give you an idea of where the touch screen thinks you're pressing and/or if it is even registering your touches properly (this is not a calibration, it is merely diagnostic.)
To exit "Diagnostic Mode," just cycle the ignition.