Am I getting old? Or is it my car? A lot of drivers have probably asked themselves that question if they struggled to make out distant points on the road. We’re not responsible for medical issues, but we’ll give you information on worsening lights.
A broken lamp will (hopefully) catch your attention immediately; a gradual loss of light won’t. You get used to it because it drags on over a long period of time. But at some stage you can’t help thinking that it used to be better. That’s when the search for the cause begins.
The naked eye alone will identify one possible reason: milky, scratched or otherwise damaged headlight covers. They scatter the light in all directions instead of guiding it where it belongs, namely the important parts of the road. That’s not just a few meters in front of the bumper, but 50 meters and beyond. Unfortunately, there’s no sensible cure for worn headlight covers – except replacing them, which usually means replacing the entire headlight.
Before going down this expensive path, however, it’s worth looking for other sources of faults that may well cause the problem. These include voltage drops where too much power is lost in the cables, relays, connectors or switches. Sadly, voltage drops tend to increase as time goes by. Comparing the voltage at the generator or battery terminals with the voltage at the lamp base will give you the answer. It shouldn’t be above 0.5 volts, and overall there should be at least 13.2 volts. There are a few ways of tackling low voltage, but that’s a job for a mechanic. Replacing parts based merely on suspicion is usually more expensive.
Eliminating loss of light is easiest if aged lamps are to blame. Contrary to popular opinion, car lamps are not just either working or broken. During the course of their life they lose luminous flux. While halogen lamps still produce around 70 percent of the original light in the last third of their life, for xenon it can be less than half. But that’s still more than in “fresh” halogen lights. Normal lamps such as parking lights and brake lights also show a decline in performance. This applies particularly to relatively weak lamps like the ones for number plates. Sometimes an almost opaque blackish layer builds up inside the glass bulb, which filters out up to 90 percent of the light. It’s obvious what to do against worsening car lamps: replace them. And not just when there is no more light coming out at all. Some people will be amazed how much better they can see all of a sudden. A bit like a fountain of youth. Not for the driver, but for the car lights.