After a couple of hours going round in circles I am taking a time out as I am getting nowhere fast.
The Trailer wiring is Fine. All lights and electric brake ok apart from no brake lights when connected to car. I have had a look on rave and it says a BW colour wire comes out of the trailer ecu in the rear wing, goes to trailer plug. I have no BW wire coming out of mine. I presumed it would be red coming from pin 6 on the trailer socket. Anyone know what colour wire for the brake lights at the trailer ECU, could there be a fuse blown somewhere? The ones in the rear are all good, car is 2003 td6 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

I might be wrong on this but is the B/W wire not between the trailer ecu and the trailer pick-up socket and not between the trailer pick-up socket and the towing socket? So you wouldn't expect to see a B/W wire at the towing socket.
The brake wire from the trailer pick-up socket to the towing socket is Red.

Thanks for the input, My understanding is the Light control module (LCM) detects the brake pedal is depressed and sends a signal to the trailer ECU which in turn sends power to the trailer plug. I have T`ed into that feed at the LCM to get the signal for the electric brake controller which works. I am not getting the power out for the brake lights from the trailer ECU presuming its the red wire. I might just bite the bullet and take off a feed from the rear cluster. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

You could test for an output at the trailer pick-up socket, adjacent to the ecu in the rear compartment.
The trailer pick-up socket is the white plug and socket next to the ecu.
If you do it the old fashioned way and just take a feed from the rear brake cluster, I would use that feed to switch a relay and take the actual feed for the trailer brake lights from the fuseboard and through the relay.
I wouldn't use the feed from the rear light cluster direct to trailer lights, I have a suspicion the LCM wouldn't like it.
I know using a relay switched from the rear brake light on the car won't upset the LCM as I have already done it.

Thanks for that, I might be looking for a bad connection in the wrong place, I did not realise that white plug was the feed to the trailer socket. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

Just had another look and it looks like the LCM feeds to the white plug, the trailer ECU connects to the white plug, the trailer plug connects to the trailer ecu so I should get power for the brake lights from the trailer ECU ( RED? ) not the white plug. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

I don't think that is correct.^
LCM to Trailer ECU to White Trailer pick-up socket to Towing Socket.
The LCM also feeds inputs to the Trailer ECU but does not connect directly to the White trailer pick-up socket.
The Trailer pick-up shown on the wiring diagram is the White Plug in the rear compartment not the Trailer Socket.
The terminology on the wiring diagram is a bit confusing particularly as it doesn't show the Towing Sockets.

there is no red wire in the trailer socket or the trailer ecu

from the trailer ecu to the socket the brake lights are fed by the black wire with a while tracer to pin 6 of the 13 pin socket, I have no idea as to what colours were used on the 12N 7 pin wiring, red is the correct colour for the 7 pin wiring , but it's a Land Rover, so it might be pink with purple spots

I can tell you that it's the black with blue strip that feeds the brake light signal into the trailer ecu from the lcm, and you are using a plugin ECU? with Landrover written on it? cos if you isn't, this is going to be a very long thread  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Brake lights are on pin one of the trailer ecu socket, so what ever colour that is  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

I've just fitted a brake controller to my MY12. I picked-up the brake light feed from the red wire at the trailer harness's white harness connector that's located at the back of the spare wheel well. Earlier model trailer harnesses may be different though.

Ok all good, I feel a bit stupid but I will excuse myself this time.
To elaborate, I purchased the car with the trailer wiring all in situe. I fitted a brake controller and modified the wiring as documented on on several web sites. The wiring in Australia is also slightly different from the UK / Land rover pin out.
The Trailer had LED Lights which drove me mad trying to rectify the flashing. Removed them and fitted old school lights.
Now for the final test and no brake lights.
I have been testing continuity with a multi meter with a buzzer, all good ever which way I test. Today I bypassed the red wire ( brake light ) from the trailer ecu to the plug on the trailer, Bingo lights work, Continuity test again all good, try without bypass, no lights. Take Car trailer socket apart, deep clean and re termination now we are in business.
I can only conclude that the connection on the car plug had a bad connection, good enough for a continuity test but not good enough for Range Rover on board diagnostics .
The wires to my trailer socket come out of the ECU, NOT the white Plug.
Thanks again for those who tried to help.
Another thing I came up against. I use a Treg Hitch mated to a Reece 50mm tongue ( Std Australian Spec). The Land Rover receiver must be 2 inch because the Reece tongue would not slide in. Out with the angle grinder to shave .5mm off all round and it slips in perfectly. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

Good to hear you got the problem sorted.
Interesting that your car is wired slightly differently from that shown on the rave wiring diagram to suit local wiring requirements.
My own car is wired as per rave diagram with the white plug and socket fitted between the ecu and the tow socket.
The wires from the ecu to the white socket are coloured as per rave with the wires from the white socket changing colours to those conventionally used in uk tow sockets.
All very confusing.

Mine is as per diagram, does that mean that I've got an odd one that agrees with the diagram

wayneg, buddy it is not uncommon to get a connection that brakes down under load, it is normally when the majority of the connection is made from rust , but we will forgive you that one as I imagine that rust is not that common in your neck of the woods. Unless you take the car surfing, literally , in which case serves you right, didn't you know that aquaphobia is a very common ffrr complaint

And 2" imperial is 0.8 mm bigger than 50mm so it's just a tight fit Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!