Hi, is that the Fuel Pump Driver Control Module for 2018 Malibu LT?Thanks for updating the term. I moved your 2nd discussion into this one and renamed the discussion to match.
The fuel pump itself is inside the tank and requires tank removal. Thankfully you don't have to do that. You should find the fuel pump power control module in the trunk on the passenger side. My info is for 2016 cars and usually covers 2016-2018 well but I am always cautious about being certain on the 2018 cars. They did make some changes in 2018 that aren't documented well and one of those changes is in the fuel system. Pull the trunk trim panel and you should see it there toward the rear.
Just to make sure we are talking about a part that looks like what is attached below... right?