11. Find and Replace a Blown Fuse

-Cars run on electricity as well as gas, and almost all of it runs through fuses. Learn where they are, how to spot a blown fuse, and how to replace them. It takes about five minutes, costs about $1, and it'll save you the hassle of a trip to the repair shop.

Vehicles today have 40 or more fuses grouped in two or more places. Usually located in or around the instrument panel near the dash, fuses can also be found under the hood and even under the rear seat.

Next time your radio, lights or other device stops working, chances are a blown fuse is the culprit. Look under “Fuses” in your owner’s manual for help finding your fuse panels. Most manuals have a diagram showing you where each fuse box is. Each fuse panel cover should have a diagram listing each device and the corresponding fuse.

Once you find the fuse box, locate the right fuse by checking the diagram located inside the cover. Then test it with a standard automotive test light. Or, buy a fuse testing tool (about $5) at an auto parts store and just touch it to each fuse in turn.
*Be sure to turn the key to the "run" position for testing.

Car fuses are color coded by amp rating. For example, a standard blue fuse has a 15-amp rating, yellow is 20 amps and green is 30. Before you buy car fuses, keep in mind that the fuse panel cover often contains spare fuses and even a fuse puller. Just be sure to replace the spares so they’ll be there the next time you need them. You can buy them at any auto parts store and at well-stocked service stations.

Note; If your new fuse blows soon after installing it, you could have problems in that circuit. Schedule an appointment with your service station or dealer for an expert diagnosis to repair the problem.

In-Line Fuses; Some accessories that aren’t factory installed may have a remote in-line fuse. These fuses can be located under the dash, under the hood or even in the trunk depending on the circuit they protect. They most likely protect an aftermarket accessory like fog lights or a CD changer. The best way to find an in-line fuse is to trace the wire from the accessory to the fuse panel. Along the way, you’ll notice a fuse container that looks like one of these shown. Open the housing to pull out the fuse and examine it. Replace it with one of the same size and amperage and snap the housing back together.

CAUTION! Never replace a blown fuse with a higher-amp fuse. Always replace the fuse with one with the specified amp rating. You may install the next-smaller-rated fuse to get you by in a pinch until you can purchase a replacement.

Required Tools and Materials

• Needle-nose pliers
  
• Replacement fuses
  

12. How to Replace Spark Plugs

Overview; Change your spark plugs yourself to maintain peak performance and high gas mileage. In most cases it's a simple job as long as you have the right tools.
You already know that spark plugs wear out. Well, “burn up” is more like it, because when a spark jumps the gap between two electrodes, it actually burns off (erodes) minute amounts of metal from each one. Over time, the gap grows to the point where the spark can no longer make the jump. That’s when you get misfires, poor gas mileage, lousy acceleration and, ultimately, the dreaded “Check Engine” light. Read on to learn how to change spark plugs. We’ll also explain when to change spark plugs.

To keep vehicles running at peak performance for longer service intervals, many car manufacturers install extended-life spark plugs. Because their electrodes are coated with precious metals that have higher melting points, these plugs can sometimes maintain a precise gap for up to 100,000 miles. But even with higher melting points, metals like yttrium (2,779 degrees F), platinum (3,222 degrees F) and iridium (4,429 degrees F) can’t stave off erosion forever. The electrodes eventually erode, increasing the gap, and, well, you’ve already heard the rest of this story.

If you’ve changed your own spark plugs in the past but are intimidated by the newer-style coil-on-plug (COP) ignition systems (pretty much the standard since 2000), it’s time to reconsider.
COP systems may look complicated, but they’re actually easier to work on than the older, distributor-based systems. Sure, you’ll have to learn a few new tricks, but the basics are still the same.

Changing spark plugs takes about an hour (for a four-cylinder engine) and will save you at least a hundred bucks in labor. You can use the same old tune-up tools (ratchet, spark plug socket and gap gauge). You should use a torque wrench to tighten the plugs. But there’s a way to get around that if you don’t have one. Just follow these steps and you’ll be tuned up in no time.

Spark Plug Misunderstanding
When you change the spark plugs, don’t be shocked to see the center electrode “worn down” to the size of a pin. If your car was equipped with fine-wire iridium spark plugs, the center electrode on those plugs can be as small as 0.4 mm when new. You’re probably used to the much larger 2.5-mm diameter on a traditional copper spark plug center electrode.

We talked with an expert to get the skinny on the latest spark plug technologies. Their advice was simple: Regardless of which brand you buy, spend the extra money for fine-wire iridium-tipped spark plugs. These plugs cost a little more than platinum plugs, but they last longer and provide a much better spark.

For longer spark plug life, buy an iridium plug with a platinum-enhanced side electrode. They’re available at all auto parts stores.

Replacing spark plugs early makes sense
Unlike manufacturers’ guidelines for oil changes, which are overly cautious, the recommendations for spark plug replacement intervals tend to be overly optimistic. For example, if you’ve already got 80,000 miles on a set of 100,000-mile plugs, they’re 80 percent worn and beginning to take a toll on engine performance and gas mileage. Worse yet, after that many miles, spark plugs have a tendency to seize in the cylinder head. Removing a seized plug can be a costly job, especially if the threads in the cylinder head are damaged in the process. When you consider the gas mile-age falloff and the possibility of seized plugs, early replacement makes sense.
*Not all spark plugs are rated for 100,000 miles. In fact, some carmakers recommend replacement at 30,000-mile intervals. So always follow the spark plug service intervals shown in your owner’s manual. But if you can’t remember when you last changed your spark plugs, you can pull them and check the gap and their condition. Once you’ve put in the labor to do that, however, you may as well change them and establish a new baseline for the future.

Do It Yourself or Take It to a Pro
The answer depends on the type of engine in your vehicle. Some of the V-6 models have very difficult spark-plug replacement procedures that require removing portions of the intake manifold. If you’re not comfortable with that level of disassembly, you should take your vehicle to a pro. But if you have an engine with easy access to the rear bank, then you can probably do the job yourself. Just be sure you gap the spark plugs properly and use a torque wrench.

The tools shown are available at online suppliers and auto parts stores. While you’re there, ask the clerk for the spark plug gap and torque specifications for your vehicle. And buy a small packet of dielectric grease. It’s also important to ask about spark plug replacement cost before making an appointment.