L322 2012 Brake Light Not Working

Afternoon all, got myself a l322 2012 tvd8 couple of weeks ago and the nearside brake light has stopped working, took the cluster out and it appears to be a sealed unit on these rather than the old unit where you could replace the bulbs in them, i stuck a 12v supply across the pins 1 at a time and all the lights within the cluster worked. Ive checked the volts at the plug on the car and got 3 pins with a perminent 6 volt supply (one of which is the brake light). Checked with the drivers side which is working fine and got the same, 3 pins with the 6 volts perminent supply. When the brake is applied the voltage on the pins doesnt change on either side (should i expect a rise in volts as the brake light switch closes?). I done the usual googling and all im getting is about light conversions.
Can someone point me in the right direction, im slightly confused as to where to look next and what the fault could be.
Cheers

lezbrucelee said:

Afternoon all, got myself a l322 2012 tvd8 couple of weeks ago and the nearside brake light has stopped working, took the cluster out and it appears to be a sealed unit on these rather than the old unit where you could replace the bulbs in them, i stuck a 12v supply across the pins 1 at a time and all the lights within the cluster worked. Ive checked the volts at the plug on the car and got 3 pins with a perminent 6 volt supply (one of which is the brake light). Checked with the drivers side which is working fine and got the same, 3 pins with the 6 volts perminent supply. When the brake is applied the voltage on the pins doesnt change on either side (should i expect a rise in volts as the brake light switch closes?). I done the usual googling and all im getting is about light conversions.
Can someone point me in the right direction, im slightly confused as to where to look next and what the fault could be.
Cheers

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Are they LED lights?

Yer its an led cluster

lezbrucelee said:

Yer its an led cluster

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Maybe it's luck that you did not destroy it applying 12 volts. I don't know the car but it's possible that it's the negative line that is switched to operate the LED's and the 6 volts is the feed for each LED.
How many pins are there in the connector?

5 pins
Ground (black common to both side although the connect is inverted from side to side), side light, brake light, fog light, indicator.
Dont think its a switched neutral system as when u check the voltage at the plug on the side light circuit im getting 14volts on the pins in the plug

I also assume that theyre not fused on each side, found F6 controlled the brake lights as offside and top light work fine until pulling F6,
The nearside did come back on at one point when i had hazards, fogs, side lights all on at the same time, but stopped working again and hasnt come back on since

upto 2010 they are controlled by the LCM, I don't have a manual for the 2012 but may be the same

backinblack said:

upto 2010 they are controlled by the LCM, I don't have a manual for the 2012 but may be the same

View attachment 257736

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Yer i dont know either, its a JLR rather than BMW LR but i dont know when the cross over was or if they used the same electrical parts

lezbrucelee said:

5 pins
Ground (black common to both side although the connect is inverted from side to side), side light, brake light, fog light, indicator.
Dont think its a switched neutral system as when u check the voltage at the plug on the side light circuit im getting 14volts on the pins in the plug

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OK so the 6 volts is a no load voltage, as backinblack said LCM. Needs diagnostics maybe.
Any sign of water ingress around where the LCM is located?

Datatek said:

OK so the 6 volts is a no load voltage, as back in black said LCM. Needs diagnostics maybe.
Any sign of water ingress around where the LCM is located?

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Not found any signs of water ingress yet, its lived its life in a garage so i would hope water ingress wont be the issue. Also should have said that nothing came up on the dash it was only my missus saw it as i pulled off the drive

Needs proper LR specific diagnostic tool.

backinblack said:

Needs proper LR specific diagnostic tool.

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Not the thing i wanted to see ;-)

lezbrucelee said:

Not the thing i wanted to see ;-)

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You need diagnostics for almost everything on these beasts

backinblack said:

You need diagnostics for almost everything on these beasts

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Yer looking like im gonna be buying a new one mine wont read much on this year of them, whats the best one for a 2012 tdv8?

Done some more digging around in the car found it is 100% not the cluster i swapped from 1 side to the other and proved the cluster so its def within the wiring or lcm. I cant find the LCM location though, ive looked behind both A pillar foot trims and its just connectors on both sides. Any ideas?

lezbrucelee said:

Yer looking like im gonna be buying a new one mine wont read much on this year of them, whats the best one for a 2012 tdv8?

Done some more digging around in the car found it is 100% not the cluster i swapped from 1 side to the other and proved the cluster so its def within the wiring or lcm. I cant find the LCM location though, ive looked behind both A pillar foot trims and its just connectors on both sides. Any ideas?

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Have a look at Blackbox-solutions they have an Android based system now that I think covers your car.

Datatek said:

Have a look at Blackbox-solutions they have an Android based system now that I think covers your car.

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Says it locks its self to the first car you use it on so cant be used on any other car, not really something i would want it to do as also got other cars that id want to use it on.
Gonna take the car to a local diagnostic guy i know see what he comes up with.

I have a Foxwell NT510 pro but it's been replaced with a NT 530. Can't see an LCM on the list of modules so I think it's called something else now.
The LCM on my 2005 is drivers footwell behind RH panel high up, I can just see the cable on the bottom peeping out.

https://www.foxwelleshop.com/ext/support-fun-list.html

Just to update the thread, ive got this fixed, it was an earth fault inside the BCM. Had to wait for a new BCM from range rover as they were on back order, but glad to say its back on the road.
The 2012 doesnt have a LCM the lights are control by the BCM which is located within the back of the fusebox inside the glove box.