Strange main beam fault. Only work when headlights on!

Hello

I have a strange fault on my 2010 d4. When I go to flash someone or turn my main beam on, it doesn’t work. The blue dash light does come on and I can hear a relay under bonnet clicking but no light. But, the main beam will work if I have my head lights on which. Says to me it’s not a fuse or a bad bulb.

the previous owner did say it’s had updated headlights fitted so there is a possibility it’s always been like this since they were fitted.

my code reader does come up with multiple codes:

left high beam circuit intermittent
Right high beam circuit intermittent
Right and left stop lamp
Both rear turn signal

all rear lights are working though. Not sure if the fact this fault for high beam is being picked up would prevent the main beams not coming on unless the headlights are on.


many help appreciated

thanks

Still have this issue. Can anyone tell me, if the car thinks the headlights are blown or not connected on the diagnostics, would it allow me to flash my main beam?

So ONLY flashing your headlights doesn't work?
You can still go from Main to high beam when driving in the dark? If so at least it'll pass the MOT!
Bit of a pain I agree but then you could simply turn your lights on and off again with the switch like I used to do back in the days of driving an old style 1960s Mini!
Must be a wiring fault, as you surmise.
Without looking at a wiring diagram I couldn't be sure, but you may find there is a separate feed to the high beams which only works when the headlights are off and it could be this that is disconnected. but I am old skool and always think in an obvious fashion which sometimes (often!) doesn't work with modern electronics.
Out of interest, if you put the sidelights on, can you flash the headlights?
That relay you can hear clicking, if it were me I'd isolate it, i.e. "find it" and see if power is coming out of the terminal that should be connected once the relay is activated. If it is try and find what it should be connected to, it may well be the high beam, but then again that may be just too simple for a modern car.
There are wiring diagrams in RAVE.
Have a look at them, if you are any good at reading them.
Best of luck!

Yes, I can flash if my head lights are on already but if not, they won’t flash but the blue light on dash illuminates and the relay clicks. My thinking is, would the electronics of the car not allow it to flash if it thinks the headlight bulbs are blown?

Jowniofownio212 said:

Still have this issue. Can anyone tell me, if the car thinks the headlights are blown or not connected on the diagnostics, would it allow me to flash my main beam?

Click to expand...

My guess is that the fitment of the later lights has required a relay be fitted, so main beams only work when the dips are on, which is actually helpful.
Unfortunately there's absolutely no way to tell what has been done in a DIY conversion, but I'm guessing I'm not too far out.

I've used a similar technique to control aftermarket DRLs, making sure they go off when side lights are turned on, which used a relay connected to the side light circuit.

as above, if you have driving lights fitted they are only allowed to be illuminated when you are driving on Full or High beam, so the dip switch should automatically put them off. This is why most peeps actuate the relay for them via a connection into the high beam circuit. That way they can only come on when high beam is on.
Anyway you've got something to go on now.

Nodge68 said:

My guess is that the fitment of the later lights has required a relay be fitted, so main beams only work when they the dips are on, which is actually helpful.
Unfortunately there's absolutely no way to tell what has been done in a DIY conversion, but I'm guessing I'm not too far out.

I've used a similar technique to control aftermarket DRLs, making sure they go off when side lights are turned on, which used a relay connected to the side light circuit.

Click to expand...

hi buddy

wonder if they’ve been upgraded to maybe cornering lights or xenons, plus where the ccf haven’t been changed

Know on the xenons there’s that ecu behind the headlight , can’t remember as well the difference between the 4 and 4.5 upgrade

gstuart said:

hi buddy

wonder if they’ve been upgraded to maybe cornering lights or xenons, plus where the ccf haven’t been changed

Know on the xenons there’s that ecu behind the headlight , can’t remember as well the difference between the 4 and 4.5 upgrade

Click to expand...

Without knowing exactly what has been fitted and exactly what was fitted, it'll be almost impossible to say with any degree of accuracy, so any suggestions will only be a guess, unless the vehicle is actually in front of you, me or anyone else.

What do you mean by 'updated'?
As of a March this year, ANY car first used on or after 1st April 1986 which has been modified with HID or LED conversions will fail the MOT test.

https://www.gov.uk/government/publi...mot-special-notice-01-21-headlamp-conversions

I've asked my MOT mate to enquire with the DVSA as to whether this applies to Series and Defenders which have had LED light units fitted as this regulation applies to headlamp unit conversions, as opposed to a new headlamp which has been designed with LED bulbs.