The number of ignition coils in a Jeep Grand Cherokee depends on the type of engine in the jeep. In a 3.7L engine, you find 6 dedicated ignition coils. The 4.7 L engine uses 8 dedicated ignition coils. In both of these engines, the Grand Cherokee ignition coil mounts directly to the spark plug.
Remove the negative battery cable from the battery terminal. For added safety, isolate the cable and set your emergency brake.
Locate which ignition coil you need to replace. Depending on the location, you may need to remove parts, like the throttle body air intake tube, in order to access the damaged ignition coil.
Release the ignition coil electrical connectors by pressing down on the on the release lock. As you press down, gently pull the connector away from the ignition coil.
Use compressed air to clean the base of the ignition coil.
Loosen and remove the nut that secures the ignition coil to the mounting stud. A small wrench or a socket set work well to do this.
Extract the ignition coil. To do this, gently pull up on the ignition coil. As you pull, slightly twist to break the seal between the cylinder head and the boot of the ignition coil.
Clean the top of the spark plug, using compressed air. You can also clean the o-ring for the ignition coil.
Insert the new ignition coil. You want to guide the coil base over the mounting stud.
Replace the mounting nut and tighten it. If you have a torque wrench, tighten to 70 inch pounds (8 Nm).
Snap the electrical connectors back in place.
Reinstall any other parts you removed during the unistall process.
