The Ford Explorer has several different engine options available, but no matter what engine is in yours, the process of changing the spark plug wires on your Explorer is the same. The spark plug wires are critical to the operation of the ignition system as they carry the electrical charge from the distributor or coil pack to the spark plugs. A faulty wire will allow a drop in voltage or may not deliver any, causing the plug to fire with a weak spark or not fire at all. If you suspect the wires are defective, replace them with a new, high quality set of wires.
Open the hood of your Explorer and locate the negative battery cable at the battery terminal. There is a large minus symbol on the battery indicating the negative post or terminal. Loosen the retaining bolt on the negative cable end, then remove the cable from the battery. Isolate the cable end to avoid it accidentally energizing the ignition while you are working.
Locate the spark plug wires on the engine. Older models that have a distributor will have wires running from it and connecting to the spark plugs on the other end. Newer models will have a coil pack and no distributor. These systems have spark plug wires running from the coil pack directly to the spark plugs.
Select the first spark plug wire to change. It really does not matter where you start, but do not take off more than one wire at a time. If you mix up the location of the wires, the engine will not run right, if at all.
Grasp the spark plug wire at the boot on the distributor or coil pack. Twist it slightly as you pull straight off the terminal. Do not pull on the wire or you may rip the wire out of the boot. Follow the wire down to the opposite end and, again, twist and pull from the boot to remove the wire from the spark plug.
Lay the old spark plug out straight on the ground or a workbench. Match the length of the old plug wire to one of the same length in the new set, then discard the old wire.
Install the new wire by placing a small amount of dielectric grease in each of the boots on the end of the wires and then pushing the wire onto the spark plug until it snaps in place. Route the wire up to the distributor or coil back and push the wire on the connector there.
Move to the next wire and repeat the process. Continue removing one wire at a time, replacing them with new ones and working around the engine until they have all been changed.
Connect the negative battery cable to the negative terminal on the battery, then tighten the retaining bolt with a wrench. Start the engine to verify that it is running properly and that all the plugs are routed correctly. Close the hood.
