Headlights Getting Dimmer on R171

[girlagogo]

A few weeks ago I noticed, when driving my R171 300 V6 at night that the main lights had suddenly become dimmer. I always have the lights set to auto and they stay on after locking and leaving the car (called "Welcome Home" light setting?).

When looking at the lights they are still bright, as in working, but the road isn't lighting up as much and they only seem to be lighting up a lower section. The positioning hasn't been adjusted so not sure what's going on. Is it possible for bulbs to go dim first before completely blowing or could this be something else?

Battery is fine, no problems starting. However tonight, the "Dipping Beam Right" warning light appeared on the dashboard so the right bulb has now gone. On previous cars when bulbs just blew, the lights didn't get dimmer - anyone else come across this?

 

[Blobcat]

Mine have just “gone” previously / what’s the condition of the lenses? And are the inside of the headlights all clean?

 

[sonic]

Put a meter on the battery with the engine & lights on, you should see about 14 volts.
Unlikely to be both bulbs at once, as Blobcat has said are the lenses clean?

 

[girlagogo]

I'm afraid I don't have the tools do the checks so would have to take to a mechanic or garage. Would Halfords do this? I have always had them replace head lights bulbs on previous cars

 

[Blobcat]

I'm afraid I don't have the tools do the checks so would have to take to a mechanic or garage. Would Halfords do this? I have always had them replace head lights bulbs on previous cars

Are the front of the headlights clear or milky?

 

[sonic]

I'm afraid I don't have the tools do the checks so would have to take to a mechanic or garage. Would Halfords do this? I have always had them replace head lights bulbs on previous cars

Any decent garage should be able to check your battery & charging state even Halfords.
As you are still starting & driving the car even in this cold snap I wouldn't expect a problem there.
You mention the main lights, do you mean the headlights on dip beam?

 

[girlagogo]

Are the front of the headlights clear or milky?

They look clear

 

[girlagogo]

Any decent garage should be able to check your battery & charging state even Halfords.
As you are still starting & driving the car even in this cold snap I wouldn't expect a problem there.
You mention the main lights, do you mean the headlights on dip beam?

They are on the dipped beam but, only last night now the right bulb has gone as the "Dipped Beam Right" indicator came up om the dashboard. This makes me think that the left one will go soon and that the bulbs were on their way out after all

 

[Chrishazle]

It's a 20 minute job to change a headlight bulb on an R171 once you know how - but it involves removing the appropriate wheel and releasing the front of the wheel arch liner to access the bulb holder. Blobcat did a few posts on here not that long ago with photos, see here :

Headlight bulb replacement on a r171

Hope this hasn't been asked before, couldn't find any reference, low beam headlight bulb has failed and so has the left side light on the SLK350. (well the n/s has been intermittent for a while :oops:) Does the front bumper and headlights really have to be removed to change the bulbs?

forums.mercedesclub.org.uk

My experience here : https://forums.mercedesclub.org.uk/...-r171-headlight-bulb-replacement-pita.198397/