The spark plugs on a 2004 Chrysler Pacifica (assuming the 3.5L V6 engine) are located
on the top of the engine, under the plastic engine covers. You'll need to remove these covers to access them. They are arranged in a V-pattern, one plug per cylinder. There are no readily accessible plugs on the side of the engine.
To be precise about the location relative to other engine components requires a shop manual or a detailed diagram. Consult a repair manual specific to your vehicle for detailed illustrations and instructions. Improper removal or installation can damage the engine.
