Member Since: 20 Nov 2013
Location: Scotland
Posts: 107
No brake lights on trailer?
Looking for suggestions as to why the brake lights have stopped working on the trailer.
I check the issue was with the car by plugging in other things to find the brake lights don’t come on either, assumed it must be the 7 pin plug, just had a horrific experience replacing that but no change.
Fuse I don’t know about or dodgy wire/connection somewhere else?
3rd Dec 2017 6:00 pm
OJ
Member Since: 01 Oct 2017
Location: Loch Leven
Posts: 725
Fuse, lower panel fuse box behind glove box
3rd Dec 2017 6:06 pm
Carl R
Member Since: 05 Sep 2014
Location: Chelmsford
Posts: 49
The D3 has a small fuse unit on the nearside rear storage compartment for the towing wires.
3rd Dec 2017 7:49 pm
OJ
Member Since: 01 Oct 2017
Location: Loch Leven
Posts: 725
3rd Dec 2017 7:52 pm
development_cycle
Member Since: 20 Nov 2013
Location: Scotland
Posts: 107
Right so after looking in the fuse box behind the glove box as OJ-LR4 suggested and drawing a blank, I went to the owners manual and found the third fuse box in the boot as Carl R mentions. There I found the blown fuse 😎
Replaced it and boom! Gone again, I tried one more time and listened as I turned the ignition on and heard it go, before turning on the lights or pressing on the brake pedal.
Any suggestions? I’m thinking just trace that wire and expect to find it earthing somewhere.
3rd Dec 2017 10:41 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
Yeap. Trace wiring.
May need to remove the rear light???
3rd Dec 2017 10:57 pm
OJ
Member Since: 01 Oct 2017
Location: Loch Leven
Posts: 725
Apologies my D4 fuses are obviously slightly different, forgot the D3 had another lot in the back, the wires should go from the plugs in the boot through the body under the light towards the towbar socket, depending on the loom used there may be more plugs behind the bumper, if so another loom runs from these to the 7 pin or 13 pin plug sockets.
You could check the plug wiring and see if there is any water inside or a loose wire on the back of the plug, if thats all ok you need to trace back to the socket in the boot to find out where the short is. Pin 6 is for the brake lights. I seem to remember reading in another post of Martins LR use different colours in their dedicated loom pins 8 on just to help confuse things.
Photo of plugs which may help
Cheers OJ
3rd Dec 2017 11:27 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
If you struggle finding the short you can replace the fuse with a bulb (as a test aid).
Jam the brake pedal down with a bit of wood and move seat forward.
The bulb will light up. Then wiggle the towbar wires around. When the light goes out, you have found where it is shorting to metal.
4th Dec 2017 1:29 pm
OJ
Member Since: 01 Oct 2017
Location: Loch Leven
Posts: 725
good idea Pete if you’ve not got a multimeter.
4th Dec 2017 1:37 pm
raincloud
Member Since: 16 Aug 2011
Location: nottinghamshire
Posts: 136
I had similar problems - insulation on wiring loom had worn through as loom was rubbing against rear bumper next to the harmonic damper weights - cured with a new loom
4th Dec 2017 5:47 pm
development_cycle
Member Since: 20 Nov 2013
Location: Scotland
Posts: 107
so the latest on this is that I started to trace the wires from behind the rear passenger light cluster, definitely found at least 4 places where the wiring has been rubbing in the body, and in one place where it has almost cut right through all the wires on one loom, the one I don't use hence I never noticed.
Figured best to remove and see the damage. In my opinion both of the "outer" wiring looms are totally fooked! I'll probably replace the standard one only for now as I don't use any of the features of the extended features (no caravan).
Will add pic's soon
29th Jan 2018 12:56 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
I guess you can get some standard black 7 core towbar cable to power your normal socket.
And join it to the landrover towbar cable high up or by the light or better still just inside the car.
This cable should offer more protection, and not be so bulky that is rubs in places
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my D4 fuses are obviously slightly different, forgot the D3 had another lot in the back, the wires should go from the plugs in the boot through the body under the light towards the towbar socket, depending on the loom used there may be more plugs behind the bumper, if so another loom runs from these to the 7 pin or 13 pin plug sockets.
