Thread: D4 & LED Caravan Lights

G'day mates

A little history about the trailer towing saga.

All vehicles manufactured and or sold in the EU must conform to the E/ECE/324 – E/ECE/TRANS/505 European trailer lighting regulations. Not only are the wire colours and the pin usages in the connectors different to the Australian standard but the EU also has two tail light circuits where we have only one.

I agree that the Australian dealers should convert the trailer wiring to the Australian standard before handing over the vehicle to a customer. A couple of dealerships that I know of in the Sydney region do (or at least did do) the conversions. But it didn't always happen.

If I remember correctly, a long while ago, Land Rover Australia did sent out a bulletin to the dealerships about doing the trailer wiring conversions. Perhaps it is time for Land Rover Australia to get up the dealerships for not doing the conversions???


Lamps (light bulbs) on the trailer draw lots of current (amps) and are easy for the computers in the vehicle to recognise. LEDs draw little current and are very difficult to RELIABLY monitor as only a little dirt or corrosion in the trailer connector or wiring can give lamp failure warnings even when the LEDs appear to be working and, of course, lamp failures can cause other problems also. (see below)

The vehicle’s computers are informed when a trailer is connected so that their safe towing features can be activated

Body Computer – enables the operation of the trailer telltale in the Instrument Cluster (a legal requirement in many jurisdictions). The rear fog and reversing lights on the vehicle are disabled to eliminate the reflected glare, back into the vehicle, from front surfaces of the trailer and the rear parking aid sensors are disabled.

Suspension – at highway speeds automatic changes to ride height are disabled to reduce the possibility of directional instability in the vehicle/trailer combination.

Anti-Lock Brakes, Stability and Traction Control – when in motion alternate strategies can be applied to control the dynamics of the vehicle/trailer combination.

Power Train Control – engine fuelling, throttle response, automatic transmission shift points, enhanced dynamic engine braking, etc. for the vehicle/trailer combination.

Trailer lighting – stopsthe park, stop and turn signal LEDs on the trailer from continuously blinking.
Note: not all vehicles have all of the above functions

Sure you can make up your own adaptor or have someone make one for you if you are not all that handy with power tools and a soldering iron. BUT!!!!!!

Safe towing to you all

Wires

Originally Posted by Grappler

I installed 8 ohm dummy loads for the L and R indicators and that solved the problem of the vehicle not sensing the trailer, but the trailer still strobed like an emergency response vehicle. The solution was to include auto relays in each of the indicator circuits. See pics attached of my homemade solution. All other circuits pass direct through to the trailer.

The circuit also allows the traction control to disable the raising suspension, automatically, when selecting rock crawl. It also defeats the rear parking sensors when it is attached.

The question is really about the comment where "all other circuits pass thru".

Do your trailers have brake lights bulbs separate from the signal light bulbs?

Like your D3, the LR3 has the brake light bulbs separate from the signal light bulbs, but on our trailers, for the most part, the brake light and signal light are the same 21 watt filament located in the same bulb.

The LR NAS harness wiring combines the filaments so all works fine as long as the trailer has the old style filament bulbs. I was considering building an adapter box but I wondered if I can just ignore the brake light circuit?

I figure that I can as there is no separate brake light conductor in the NAS trailer plug. Also for what we call the tail lights or running lights, I presume that circuit can be ignored and "just run thru" as that circuit is the same as your D3 and is not monitored. That would make sense as during the day, only the signal and brake lights would be powered - well we have daytime running lights here so the tail lights are illuminated all the time.

Hence the question, are the brake and signal filaments in trailers in Australia combined or separate? I suspect separate, same as the vehicles.