WARNING: This page is about a different car, the 2020 Chrysler 300 and 2019 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of CHRYSLER GROUP, LLC
The 5.7L and 6.4L engines use two knock sensors (1) and are bolted to each side of the cylinder block (outside) under each exhaust manifold (3).