[JohnnyRay]

I don't know. I do know there is only one of the "black boxes" on the rear drivers side inside the rear panel above the exhaust. There is not the same thing on the passenger side.

I bought the vehicle used and everything was working great for a couple of weeks. I happened to notice that the slit where you move your foot to open the hatchback was filled with mud. I sprayed the mud out with a hose and took it through a car wash. That was the first time I experienced weird electrical problems. Restarting the car cleared the problems. 2 additional times over the course of several weeks I had the other strange electrical problems after car washes.

This is on my 2017 Acadia Denali. Yours may be different. I do know that I was having intermittent electrical problems (all very different, but all likely connected to the CAN bus network in the car) after every car wash. Since sealing the slit on the bottom of this module, I have not had any problems after several similar car washes for many weeks now.

Could be coincidence, I am just sharing my experience because it was easy to deal with and may solve other people's problems.

If not, you can always remove the tape and start visiting the dealer. That's what I plan on doing if the problems start happening again, but I do not look forward to the inconvenience.

 

[speleos]

...
This is on my 2017 Acadia Denali. Yours may be different. ..

It reads like that's the liftgate foot activation module. That module was moved to the left side of the rear bumper on my XT5 and the newer Acadia (at least 2020 refresh) - not between the bumper and wheel well like yours.

 

[PidiumKen]

My son came home yesterday and said he "smelled something" and the Driver's and both rear doorlocks had quit..neither lock or unlock. ...upon inspection, we found that the windows, seat memory, engine key reminder and other things had quit too. Went on other forums that lead us to find that there was a copious amount of water under the carpets on both passenger and driver's front.... apparently caused by blocked drainage lines from the sunroof.

We had to remove the carpets and pads....(just unbolt the front seats) and dry it out, then cleared the drains (youtube videos cover this).... removed Driver's door panel as the rubber connector cover was full of water....unplugged everything..., all while the passenger door lock and window worked fine.... long story....that awful fuse panel above the glove box....one 25A blown fuse and two burned relays.... takes chunks out of your skin to remove....bingo, replaced the DENSO relays with new GM part 13500126 's, replaced the fuse and Bob's your uncle....all good...took about 10 hours to remediate and my son has a new attitude about GM Engineering.

I suspect the drainage paid a part in the relay failures. We also noticed and reseated all the grounds....they are conducting, so it's probably best to disconnect the battery before starting to troubleshoot. When removing the passenger carpet, the dash and entertainment system activated....caused by disconnecting the seat's airbag connector....makes one wonder. Remember, persistence pays off, or overpay the garage for their education.