Thread: Discovery 3 LED trailer lights

Originally Posted by Crosbo

Although the pulses on my D3 are not enough energy to cause the 40 amp / 14VDC relays that I am using to close, the 79+ ohms of resistance the relay is providing, is not being recognized by the vehicle as a trailer being connected.

Just put a 6 to 8 ohm resistor in parallel with the coil on the relay, the resistor will have to have a 10 to 20 Watt rating. With 20 Watts you should be able to handle the blinker getting stuck on continuously. Ten Watts you might get away with given the duty cycle of the blinkers but the resistor will get hot, A 20 Watt with a built in heat sink will be the safest.

If you don't mind waiting for the post these are a good deal 4X LED Turn Signal FOG Run

if it is just a trailer then this is a better deal 2X Flash Rate Load Resistors LED Turn Signals Indicator Blinkers Controllers 25W | eBay

I noted the two pictures above and got to thinking of my album related to the NAS tail light setup and LED concern. Hence I thought I would post the link as three of the files at the bottom may be of interest.

My solution as detailed was based on data I got off AULRO and works well. Within the one pdf are a number of links back to AULRO which may be of interest for review of past solutions.

DISCO3.CO.UK Photo Gallery - NAS Trailer Socket Pin ID and Wire Colours

Thanx for the reminder bbyer...now I remember that your set-up was exactly what I was wanting to build.

Back to Home Deport for a box and the resistors should arrive on Monday. Hope to be ready to tow by Wednesday.

Thanx everyone for the information I collectively used to built my own version of a trailer harness interface. I wanted to find a way to either temporarily mount the adapter to a rental trailer or to the hitch area of the LR. Funny thing is, as I was working thru the assembly process, I kept changing the design, layout or type of mount I would eventually use. What I wound up with is a nice little package that has wound up to be very secure. I started with two 4-pin adapters, both with the LED lights so I could confirm the signal/pulse...

Next was to assemble the resistors and relays in an appropriately sized enclosure...

Once assembled, for the sake of space efficiency, I decided to forgo a 2nd hose and set of wires...

Next came the rough fitment into the hitch and tow ring cavity...

Once the fitment and tethering issues were worked out, it was time paint the assembly, allow to dry and re-fit to ensure all worked as planned.