D4 Camper towing Q

[shamirj]

Several months ago when i went to collect my camper trailer (which was old but new to me) and before driving off home connected the socket and checked all the lights worked including blinkers, brakes etc all was good. The trailer has electric brakes. Whilst driving home and lucky for me at a low speed of approx 50-60kms/hr I was approaching traffic and a short underpass when my D4 'auto' headlights activated which subsequently locked up the elec brakes on the camper.

Completed shocked I disconnected the trailer plug, and continued home. Posted my findings here and someone suggested the auto lights activating the brakes which proved to be true. So my question is WHY, why would LR wire the auto headlights to activate the brake lights or is this a european wiring problem we experience here in Aust. So glad i wasn't travelling at say 110km/hr and the brakes locked up.

[Pedro_The_Swift]

connected to the tail lights maybe.... have you physically checked what lights light up when you brake?

[kelvo]

Two issues, the main LR dealer didn’t modify the tow socket wiring when the car was first sold, and whoever fitted your electric brake controller didn’t know what they were doing with a D4.

”In this photo below i have had to find the splice joint in the wiring loom for the park light circuit (all European vehicles run a left & a right park light circuit in there vehicle wiring loom)
It is basically one wire feeding 2 Pin outs. (Pin 7 is our park light circuit & Pin 5 is our supply for our Electric trailer brake varying voltge).”

Have a read of this D4 Electric Trailer Brake Wiring (https://www.aulro.com/afvb/the-d3-d4-sticky-zone/97935-d4-electric-trailer-brake-wiring.html) as the chances are the diode has also not been fitted.

[loanrangie]

Another reason not to use the auto position.

[shamirj]

no brake controller on the vehicle

[DiscoJeffster]

no brake controller on the vehicle

So by what magic did you expect the brakes on the camper trailer to work?

[101RRS]

LR Aust is too tight to change the tow wiring in the car to Aust spec so it is still at European spec. I thought we told you this in the other thread but may be not.

In European spec there are individual power lines to each of the tail lights where here we only have one power line for both tail lights. So your standard LR wiring has one power line for left tail light and one for right tail light. The trailer is wired to Aust standard so both tail lights pick up power from one of the two available power lines in the vehicle (not sure which one).

Unfortunately for us the second taillight power line in the car when plugged into an aussie spec trailer is connected to the electric brake line in the trailer.

Hence when you switch on the vehicle lights power goes to the trailer brakes and they activate. Nothing to do with electric brake controller.

Easy fixed on a D3/RRS as there is a rear fuse box for the trailer wiring - just pull the right fuse and no power to the trailer brakes. With a controller bring in the controller at this point - all good.

The D4 does not have this rear fuse box so something similar needs to be done up front somewhere - D4 owners to advise.

Garry

[Tombie]

If you don’t intend to use the trailers brakes simply disconnect that wire in the trailer plug for now.

If you’re planning a brake controller, then the install will sort your issue.

If the trailer is over 750kg it must have working brakes.

[kelvo]

no brake controller on the vehicle
Have a read of the 1st post in the brake controller fitting guide D4 Electric Trailer Brake Wiring (https://www.aulro.com/afvb/the-d3-d4-sticky-zone/97935-d4-electric-trailer-brake-wiring.html) it has the answer to your issue. Yes I know you don’t have a brake controller, but you still need to read the post.

[kelvo]

D4 owners to advise.

Garry
I already have, in post 3 of this thread.

[jh972]

Another reason not to use the auto position.

Nope - it would still do it if you turned them on manually