Section 121 (Ignition System (Service Information)): Sensor-Knock: Description
WARNING: This page is about a different car, the 2007 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
Two knock sensors are bolted into the cylinder block under the intake manifold on the 3.7L & 4.7L engines.
Two knock sensors are also used on the 5.7L engine. These are bolted into each side of the cylinder block (outside) under the exhaust manifold.