W211 Headlight fault

[Watchcame430]

Hi All,

Had the car now for nearly 3 weeks and woke up this morning to a flat tyre and the rear air suspension on my 2005 E270 on the floor.
Undeterred I started to change the headlamp bulbs as I couldn't see anything when I took it out for a drive the other night.

Incredibly with new bulbs I have no headlights. Sadly I hadn't checked before changing them.
I thought well hopefully a fuse or relay so did a google and a youtube search to find out where the fuse is for the headlights.
Nothing. Seems to be some kind of state secret.
Still not put off I popped the cover on the side of the dash to get the fuse board locator paperwork out.
Nothing. Most of it in German but that aside I see nothing referencing headlights.

Anyone tackled this giant mystery before? I did a forum search and nothing towards the top of the pile.
Seems very strange indeed.

Edit - to add it is a halogen headlight car. No Xenons.

 

[Ted]

there is no fuse.
The current is electronically limited by the front SAM.

 

[Watchcame430]

That sounds ominous.
I am hoping someone else comes along and has had this problem.
I need to fault find it in the most logical way (also known as cheapest first )

If no fuse and I guess no relay might the best thing be the switch I wonder?

What's annoying is the car passed its MOT and serviced at Mercedes recently.

 

[W1ghty]

That sounds ominous.
I am hoping someone else comes along and has had this problem.
I need to fault find it in the most logical way (also known and cheapest first )

If no fuse and I guess no relay might the best thing be the switch I wonder?

What's annoying is the car passed its MOT and serviced at Mercedes recently.

Try the old bulbs again ?

 

[Watchcame430]

I will but I think wishful thinking. They were so bad it would make sense for them not to be working.
Will definitely try changing them but I would like to gather some other options too include perhaps buying a new switch etc.
Chances are someone will have seen this before? Fingers crossed!

 

[Ted]

I would go with what @W1ghty says first. Check the plugs are fully home on the bulbs. Do both main and dip not work? If so- I would then be checking the earths - it’s a brown wire.
Rather than guessing, put a test light on the wires and test from the bulbs back.

 

[Watchcame430]

I would go with what @W1ghty says first. Check the plugs are fully home on the bulbs. Do both main and dip not work? If so- I would then be checking the earths - it’s a brown wire.
Rather than guessing, put a test light on the wires and test from the bulbs back.

Will do.
Dip is separate at the bottom and always on?
My concern is I am working abroad next week so clock ticking on parts for the weekend.
How would I test the Earth? I do have a set of testers somewhere. Thanks so much

 

[Ted]

Dip is only permanently on if set in one of the menus as a sort of drl.
Simplest way to test the earth is to put one probe of an ohmmeter into the earth pin on the bulb holder and the other to a good clean point on the body or engine - should be zero ohms.
I would do it a bit different, but let us know what you find.

 

[Watchcame430]

An update on this. Thanks for the input, really helpful.
Turns out that "Headlamp bulb" I changed is main beam.
The "Headlamp bulb" is known as dipped beam. I always thought dipped beam was side light.
Long story short i had googled it and even watch you tube videos who misdirected me.
I have only had Xenons for last 10 years so this really has me going back in time and it is a revelation to find out there is no such thing as a headlamp bulb.
Have ordered Night Breakers for the outer lights. Hopefully that will fix those issues.
Now to sold the mysterious air suspension fault that appeared the same time as the puncture.

 

[W1ghty]

An update on this. Thanks for the input, really helpful.
Turns out that "Headlamp bulb" I changed is main beam.
The "Headlamp bulb" is known as dipped beam. I always thought dipped beam was side light.
Long story short i had googled it and even watch you tube videos who misdirected me.
I have only had Xenons for last 10 years so this really has me going back in time and it is a revelation to find out there is no such thing as a headlamp bulb.
Have ordered Night Breakers for the outer lights. Hopefully that will fix those issues.
Now to sold the mysterious air suspension fault that appeared the same time as the puncture.

Well played buddy , you saved some money there

 

[Gbrowncls55]

Hi All,

Had the car now for nearly 3 weeks and woke up this morning to a flat tyre and the rear air suspension on my 2005 E270 on the floor.
Undeterred I started to change the headlamp bulbs as I couldn't see anything when I took it out for a drive the other night.

Incredibly with new bulbs I have no headlights. Sadly I hadn't checked before changing them.
I thought well hopefully a fuse or relay so did a google and a youtube search to find out where the fuse is for the headlights.
Nothing. Seems to be some kind of state secret.
Still not put off I popped the cover on the side of the dash to get the fuse board locator paperwork out.
Nothing. Most of it in German but that aside I see nothing referencing headlights.

Anyone tackled this giant mystery before? I did a forum search and nothing towards the top of the pile.
Seems very strange indeed.

Edit - to add it is a halogen headlight car. No Xenons.

If you ever have to go into the fuse box on the side of the dash make sure you have a uk fuse diagram, otherwise you will find rhd boxes are upside down for eu diagrams.

 

[Watchcame430]

Thank you! Sorry for delay in responding.