Thread: The rear fog lights come on when I plug the trailer in

Originally Posted by HedleyLamar

Hi Pete,

I have a similar problem here as I just purchased a camper trailer (not LED lights) and went to plug in the trailer and the rear brake lights on the D3 come on. No ignition on. When you mention wiring, who should I take the car/trailer to? Will any auto electrician do, or does it need to be someone who knows Land Rovers? I usually use ULR for all my servicing, but if you can recommend anyone, I'd prefer someone that knows what to look for. Problem is I don't wan tot tow it plugged in or without lights....any idea's. I could try testing the plug, but I'm no electrician.

Cheers Neil.

Hi Hedley,
I work for MLR, so the guys over at ULR should know what they are doing.
I would prefer for it to be sent to a dealer as they know the vehicle a little better than the local Auto Elec. The dealer also has a reputation to withhold.
So the work is guaranteed.
Be happy to have a look at it at MLR also if u wish. Let me know if u do.
Cheers.

Originally Posted by DDdisco

I followed sniegy's advice and disconnected pin 2 in the trailer plug (not on the vehicle). I still haven't gotten around to finding out what it used to do, but it has cured the problem. The brakes and the fog lights work as they should. I guess one day I'll find out what that wire is connected to!

I might also have a look at this as it is quite possible that what I saw were the fog lights and NOT the brake lights. Maybe this is the problem? Also could the std plug on the car be wired incorrect? I pulled it apart on the weekend, but as the wiring loom is so tightly fitted, it's hard to tell what coloured wires go to which pin. I even dropped the spare tyre as it appeared to foul the loom but it was not the case, just neat & tidy wiring.
I'll give ULR a call thanks Pete and go from there, if I have no luck I might pop in to MLR as i'm in the area at least 2 days a week.

The way I could tell it was the fog lights is the tell-tale on the dash came on as well. It didn't matter what position the key was in.

DDdisco - whats the chance your horse float has a small battery onboard? (to operate breakaway brakes required for over 2000kg)

Yep, it does (quite a big battery actually). I thought that it may be a charge wire for that, but I've also got a built in charger that charges the battery when the float is plugged in to 240V to run the fridge, lights, etc. I also figured that the trailer plug wire was probably too small to be using as a charge wire for the battery anyway.

We always plug the float in at home before going anywhere to cool down the fridge, then plug it in again when we get there if camping. I also check the 12V internal lighting before going anywhere to make sure the battery has got enough charge for the breakaways.

Cheers

Originally Posted by DDdisco

Yep, it does (quite a big battery actually). I thought that it may be a charge wire for that, but I've also got a built in charger that charges the battery when the float is plugged in to 240V to run the fridge, lights, etc. I also figured that the trailer plug wire was probably too small to be using as a charge wire for the battery anyway.

We always plug the float in at home before going anywhere to cool down the fridge, then plug it in again when we get there if camping. I also check the 12V internal lighting before going anywhere to make sure the battery has got enough charge for the breakaways.

Cheers

OK - usually if there is no other charging line (like a Andersen plug) the #2 pin is used as a trickle charger - the Aus standard for a 7 pin trailer plug is Aux or Reverse on pin #2. The Battery for the breakaway systems are normally very small (only9a/h) so the 7 core wiring isn't an issue, the point that some one added large batteries without changing this would be of some concern.

On the Float you have a charging wire on Pin#2 running straight to the battery (or maybe leaking through a fridge line ect)- when plugged in, it is powering the Rear Fog Lights which (same as my car) is on pin #2 on the car socket. I have cut and insulated that wire, about two inches from the Trailer Control Module, as no trailer that I have seen or heard of in Aus is fitted with rear Fog Lights.

I'm completely dumbfounded why the Land Rover dealers are delivering genuine fitted trailer wiring that doesn't conform to any trailers or standards in the country of sale - to the point where the owner is unable to legally tow larger trailers without modification - due to the tail lights on pin #5 issue as well as this one, there are ADRs that this is failing and we're not buying cheap Korean hatchbacks either are we...

Harlie,
When the vehicle is not touched & no trailer brakes are fitted it is fine & conforms to Australian imports for a foreign vehicle.
As the wiring to the vehicle operates the things that are required.
R-turn 1
L-turn 4
Parkers 6
Earth 3
& Stop 7

The only 2 others that we use, as an "Auxilary" "If Required" are pin 2 (12v feed/rev/fog) & pin 5 (trailer brake feed/12v feed).

The dealers delivering these vehicles are NOT doing anything wrong.

If Mr Joe Bloggs purchased a vehicle to tow his trailer to the tip every weekend, he would not have a problem & NO modification would be required.
If you didnt fit trailer brakes again, you would not even know.

Cheers

Originally Posted by sniegy

If Mr Joe Bloggs purchased a vehicle to tow his trailer to the tip every weekend, he would not have a problem & NO modification would be required.
If you didnt fit trailer brakes again, you would not even know.

Cheers

Other than the continual message on the dash telling me my trailer tail lights need to be checked??? Because the car is wired with 2 tail light circuits to the trailer socket and no trailers in the country are setup like that.... I did only tow a box trailer to the tip at the start, and I did know something was wrong.

So what you are saying is that our Dealers advertise these vehicles as suitable to tow a box trailer to the tip and no more?

For a 100k+ vehicle that IS marketed as a series tow vehicle that's a bit poor. And as you know #5 IS required to tow anything over 750kg. My Vogue was wired for brakes by the Dealer with the instructions of 2000kg+ being required. When I took the car home I could not legally tow a heavy trailer with it due to this issue. We all know how much a RR Vogue costs + 1000 for the brake wiring and it still cannot legally tow a 2000kg+ trailer, which in today's standard is not that big!?!? It did at least fix the "Check Trailer Tail Lights" message....

Now I acknowledge that you are an invaluable member of this group and this is no way an attack on you, but do you really think that this equation is acceptable to the consumer? This is exactly why many people buy, and are even pushed (by van or marine industry) toward the Jap brands, and the LR dealer network, by treating consumers like I was stuffed around are even trying to push us enthusiasts away. As I said - why deliver a product, let alone an expensive product, that does not conform to any standard in the market of sale - just to p*ss people about? I've honestly got better things to do than try and work out what's wrong with my absurdly expensive towing wiring, because the dealer couldn't be bothered to do it properly. And this thread shows I'm not alone...

Note: Dealer in Q is not even in the same state as Sniegy