Mercury 7T4Z-12A699-AB Engine Knock Sensor

Disconnect the negative battery terminal. Find the knock sensors behind the intake manifold on the front side of the block. Remove the manifold, disconnect the sensor's electrical connector, and remove the bolt and sensor. Install the right-hand sensor with the wire end at 6 o'clock, and the left at 3 o'clock. For V6 models, sensors are between the cylinder heads. They share a wiring harness and must be replaced together. Remove the intake manifold, thermostat housing, coolant tube, disconnect the sensor connector(s), remove the bolt(s) and sensor(s). Reverse the process for installation, and tighten the new ECT sensor.