Headlights.....Candles have higher light output!

[Shaddow]

Morning All,

 

An issue I have had for a little while now is that my MB6 seems to have lost a lot of the light output form the headlights.

Unfortunately I cant pinpoint an exact time this happened, but believe it may have slowly happened over time.

 

With headlights on in complete darkness it light output is very low. Its as if they are currently set to "Candle light" power setting.

 

I have tried replacing them with standard H4 bulbs, 100W H4 bulbs and 2 different HID kits. 

The HID kits give the best light, but still sure my phones torch has more light shining out of it.

 

Is this something anyone has experienced before? 

 

Possibly some electrical issue, or headlights distorted on the inner lens?

 

Headlight level is set correct and I can see the area where the beam is focused, so its not an "Adjustment" issue.

 

Even High beam is CR@P! It just lifts the beam up higher, but because it now goes further before being reflected back of road, trees etc...the light looks even weaker.

 

Visual inspection of the lens does not look bad. They are not misted up or look any different to what I would expect.

 

Any help would be much appreciated.

[Krzys]

Have you tested what voltage the lights are getting? Maybe there's a failing earth somewhere causing them to dim?

[Shaddow]

Not tested. Will get the multi meter on it tonight. Any idea what it should be?

Also think I might have a dying alternator as the car sometimes struggle to start, even after several long journeys and the battery is only about 2.5 years old (Bought from Honda).

Not sure if this could contribute.

[Krzys]

Could be a factor, I would say to look for voltage between 12-14 volts with the engine running and lights on.

[Dave]

I know on a lot of cars Ive owned there's been a voltage regulator for headlights, so I'm assuming our M's have the same.If I remember rightly, it's on the driverside front inner wing? A small black box (please someone correct if wrong). As Krzys said, check the power getting to the bulb sockets and see if its low, if it is, could be bad earth, voltage regulator or both mate. Should be easy enough to sort though.

[EmZvr]

..but believe it may have slowly happened over time.

 

To me this sounds like wear of the reflective coating on the headlights. But to find out for sure you have to open a headlight or borrow one from someone. So first try the things proposed above.

[Shaddow]

Thanks for the info.

 

Checked last night and earth from battery seems good all over. Alternator also seems to be working fine giving around 14V across battery with engine running.

 

Have not measured voltage to light plug. Anyone know what it should be? What will be considered  low?

[Krzys]

I'd say anything below 12v (outside of a reasonable range).

 

Test it and see what it comes back with.

[Gel]

12.6 volts is what you should expect at the bulb plug (engine not running).

 

Be sure to check for any plug resistance that may have occurred over the years.

 

Fingers crossed you do indeed have a voltage drop problem.

[CARiD]

If you had problems with both halogen bulbs and HID kit - than it should be the voltage problem, or maybe loose ground connection.

[Shaddow]

So iv checked and voltage going to plug is around 12.6V with engine off.

 

Does this mean I have a bad earth somewhere? What is the best way to track it?