Quick Fix to Your BMW 318i Headlight Problems
Ideally, the BMW 318i headlight assembly and bulbs are replaced every after two or three years. But when a problem appears earlier than expected, you have to address it right away. Here are the common problems that car owners encounter involving headlights:
Both headlights don't work
The cause may be any or some of these: bad headlight fuse, wiring, headlight switch, bulbs, relay, or control module. Identify what causes the problem. Start by checking the fuse. (Refer to your manual for the location of the fuse.) If the fuse is busted replace the fuse. If not, check if it has power using a 12-volt test light or volt meter. No power means there something wrong with the wiring. But if there's power, check the relay. Shake the relay. If anything inside rattles, replace it with a new one. If the relay is intact, check the control module. If there's voltage in the module when the headlight switch is on, but the headlights don't turn on, you probably have a bad module. If there's no voltage in the module when the headlight switch is on and the headlights don't turn on, you have a problem with the switch.
One headlight does not work
Possible problems are corroded bulb socket, loose bulb, bad wiring and ground connection, or busted headlight bulb. Replace the headlight bulb that is busted or leaking. If the headlight is intact, use the good bulb on the other headlight and test it to the side that's not working. If the good bulb works, then buy a replacement bulb. If it doesn't work, then take the good ignitor module on the other headlight and test it to the side that's not working. If the headlight works, the problem is not the bulb, but the ignitor module. If the headlight still doesn't work, check the wiring. Don't suspect for other problems. Fuse, relays and other parts discussed above don't affect one headlight.
The headlight only works on high beam
If the headlight works on high beam and not on low beam or if it work on low beam and not on high beam, the problem could be the dimmer switch. Replace the entire switch to solve the problem.
Improve Visibility and Safety with These BMW 318i Headlight Maintenance Tips
More traffic accidents are recorded at night than during the day. The main reason is the drivers' inability to see well at night, which is directly attributed to poor visibility. Having a set of good working BMW 318i headlights, therefore, is an important step to improve visibility and safety during nighttime driving. Here are tips to maintain good-working headlights:
Keep your headlights clean.
A quick stop at the gas station for a quick headlight scrub will not only help improve visibility and help eliminate glare, but also prolong the life of your headlight.
Watch out for early signs of oxidation and prevent dirt buildup.
Over time, your headlight lenses develop oxidation (as in the headlights look cloudy or foggy). This is the result of weathering combined with poor maintenance. Oxidation is inevitable, but how fast oxidation develops on your headlights depends on how well you maintain the lens. Regardless, this can become a safety concern as oxidation diffuses the beams of your lights and reduces your ability to see well at night. Aside from regularly washing and cleaning your headlight lens, you have to remove oxidation as it begins to form. Use a headlight restoration kit and some elbow grease to maintain the looks of your headlights.
Watch out for excessive wear.
Headlights wear out whether we like it or not. And when that time comes, there's no other way but to buy a new set and replace the old ones (restore the old headlights if it still possible). If the headlights become yellowish, foggy, faded, or damaged, assess its condition and do the necessary actions. Whether the headlights need to be replaced or restored, address the problem immediately.
Replace your headlights in pairs.
If the time comes when you have to replace your headlights, remember to replace them in pairs, regardless of the condition of the other pair. If you replace just one headlight, chances are, the new one is brighter while the other one is dimmer. An uneven illumination can affect how well you see the road at night.