Non-functional headlights can be frustrating, particularly when the problem affects the low-beam lights, which are the lights typically used when driving. The most common problems causing headlight failure are faulty bulbs or fuses. Fortunately, diagnosing and correcting either problem is fairly simple and straightforward. The Ford Focus uses typical halogen headlight bulbs, with the exception of the SVT model. If you're having problems with your SVT headlights, consult a professional; it's equipped with HID lights,, which are very high voltage and dangerous.
Turn off the engine and open the hood. Locate the power distribution box. This box contains your low-beam fuse. It's located on the driver-side engine compartment, against the firewall.
Push the tabs on the side to remove the box cover. In the corner of the box, you'll find a plastic fuse puller. Pull it out of its mount. Look for the fuse in the number 16 compartment (don't confuse this with the fuse labeled "R16"). This is your low-beam fuse; it powers both low-beam lights.
Remove the number 16 fuse using the puller. Inspect the fuse to determine if it's bad or good. If the fuse is bad, the sliver of metal inside the case will be broken or torn apart. If the fuse is good, the metal piece will be whole.
Replace the fuse, if it is bad. It is a standard 15A automotive fuse. Insert the replacement into the slot. Test the low-beam lights to determine if the problem is fixed.
Turn off the engine and open the hood. Locate the circular-bulb cover on the rear of the headlight case. Twist off this cover to access the bulb.
Swivel the wire clamp away to unhook the bulb module. Pull the bulb module straight out of case. Examine the bulb closely. The filament inside the glass should be whole, not severed. If the filament is broken or disconnected, the bulb is bad. In addition, the glass part may have a black tint to it.
Pull the old bulb straight out of the module. Insert the replacement bulb into the module (don't twist or turn it). Wear gloves to prevent touching the glass with your hands; this can damage the bulb.
Re-insert the bulb module into the case. Move the wire clamp back into position to secure the bulb module. Twist back on the bulb cover.
