Thread: D3 Electric Trailer brake wired-photo

Hi All, Is there a reason a controller can't just be wired in like on a 'normal' car without the need for the diode and cutting into the rear harness and all that?? Seems complicated. I've already run a heavy feed wire from the battery to under the dash to feed the controller, then a heavy service brake wire to the rear of the car to supply the brakes. While I was in the fuse box under the glovebox I put a piggyback fuse in the brake light wire circuit so that should be the signal for the controller to activate. So, why can't I just run the service brake wire into the loom down near the plug or into my 12N to 7 Flat adapter or something, or even splice it into the service brake wire in the rear fuse compartment? I'm probably oversimplifying it though, just seems all a bit complicated... still have to get my noggin around it.
Is where I've taken the brake light feed from theoretically OK?

Have found that there is a difference in how the electric brake controllers have to be wired depending on whether you have "electric' brakes, or "electric over hydraulic" brakes on what you are towing.
It seems that the latter requires a constant feed to one of the wires (to keep trailer brake battery on charge), and that may be lead 2 or lead 5.
As my electric over hydraulic trailer is sometimes loaned to those with controllers set up for "electric" (only) brakes, I had the auto sparky wire me up a connector plug where he had bridged the reverse wire to supply constant power.
BUT. When reversing the trailer they have to remember to unplug the connector as the brakes come on when they select reverse and cannot reverse trailer.

Ive read through the posts and its all very informative but my question is, on my d3 2006 it has a slot in the fuse box for electric brakes and either side of the rear recovery eye above the tow bar it has a large round white plug socket and alarge black socket, there is no brake controller mounted to the dash under the steering wheel anywhere, does the vehicle come with a inbuilt brake controller? Or is the fuse there just as a point to draw power to a brake controller which previous owner may have removed? I have a teckonsha p3 to fit to the vehicle but not sure that i need to, if its built in to the car somewhere would save me the headache! Did LR option the car with a factory controller under bonnet or somewhere else in the car other than dash mounted?

Originally Posted by Poolguymark

Ive read through the posts and its all very informative but my question is, on my d3 2006 it has a slot in the fuse box for electric brakes and either side of the rear recovery eye above the tow bar it has a large round white plug socket and alarge black socket, there is no brake controller mounted to the dash under the steering wheel anywhere, does the vehicle come with a inbuilt brake controller? Or is the fuse there just as a point to draw power to a brake controller which previous owner may have removed? I have a teckonsha p3 to fit to the vehicle but not sure that i need to, if its built in to the car somewhere would save me the headache! Did LR option the car with a factory controller under bonnet or somewhere else in the car other than dash mounted?

As far as i know Disco 3 didn't come with factory brake controllers. White is 12S not generally used in OZ for towing purposes but does have constant 12v feed from battery so you can charge the battery through it as I do. Black is 12N which you use to run your trailer lights / brakes etc. See below diagram. So yes you will have to fit your P3 brake controller as per instructions in the thread. Hope this helps.
Cheers Peter

I don't think any vehicle comes with a trailer brake controller from the factory.

my neighbour has a new d5, he had the trailer brakes pack wired by an auto elect., coming down Buderim WITH NO TRAILER THE VEHICLE STOPPED, ENGINE WAS DESTROYED
a new one was put in 33000 dollars, only some intervention by the LR dealer,to the insurance Company of the sparky saw a claim succeed
now, my neighbour has that sorta money rolling around in his glove box, but he was distraught. said he'd never have any work done is it couldn't be done at the dealer, from now on

I will be fitting a tow pro elite to me D3, is this diode suitable ?

1N5408 3A 1000V Diode | Jaycar Electronics

Does anyone have a high res version of the photo from the original post?