Hello! I have been scouring the threads related to Towing/Disco V for the past week, and wondering if anyone has come across an issue like this or has a link to a post I may have missed:

When we connect the Airstream 7-pin to the Disco, the rig lights will only activate if the Disco headlights are activated manually. No big deal. But, the little green trailer lamp does not light up at all, nor does it when I use the turn signal, which the manual indicates it should. My concern is that it's not registering and therefore not activating Trailer Sway Control...which seems like a good thing to indicate when active? The Airstream is a 2018, the tail lamps are LED not sure of the rest. We did not have this problem on our other tow vehicle. I have a call in to the dealer, LR North America didn't know, and I am also going to check with the techs at Airstream service. Maybe the LEDs are not putting enough resistance into the circuit?

If I get an answer from my dealer I will post it here, but meanwhile, if anyone else knows something about this.....any info would be great. Thank you!

 

I was towing my Pop-up camper with my 7 pin setup and the trailer icon is working when I turn on the turn signal unfortunately I don't know much about airstreams but its been working fine for me and also I've been using a sway bar and is using a sway bar bad for the disco and do I need to have a specific package on my vehicle to have trailer sway assist? thanks just a question in another questionl

 

You can check the build specs with a VIN lookup (I don't have the link handy) to see about Sway Control. I am not certain if it's standard or not, or if it's standard but needs to be activated at the dealer. I'm going to see if I can bug another local person who has an Airstream parked in their driveway, and a friend who has a pop-up, to see if it happens across the board. Have not had a chance to contact the dealer yet will post any follow up info I get. Another person did PM me about a similar issue with just about the same setup I have.

 

I got to re-unite my Disco TD6 and recently-purchased 2015 Airstream today - I also had unreliable detection of the trailer first time I tried a few weeks ago. But today everything reliable (I've replaced the broken 7-pin plastic cover now and it locks the connector in tight). The detection pops up straight away without any need to turn on lights manually although I'm not sure if my auto-lights were on today or not, forgot to look. There is a table in the tow section of the Disco Manual that lists minimum and maximum currents for each of the 7-pin circuits: I assume the minimums are to do with the detection but these are only on the lighting circuits, not the brake controller and aux which have no minimums - it does not explicitly say which contact is used to trigger the auto-trailer-detect. It must be something a little clever because one of my beaten-up boat-trailers with 4-pin flat connector and only one functioning LED tail light (and no functioning turn signals :-() is detected reliably every time. One thing I didn't check is whether the Aux circuit does actually charge the trailer batteries as advertised - is that something you've ever checked mxkaybee?

I did also read the Manual section on anti-sway: it seems to indicate that everything is automatic so no obvious way to fool it into activating if the auto-detect has not worked. But with this working (together with the fairly strong warning against using a weight-transfer hitch) it would seem that the recommended setup is just a simple ball hitch without any fancy mechanical devices like sway stabiliser bars (my Airstream came with a fancy hitch and bars and I'll take them on a summer roadtrip and maybe will try them out).

Just for grins, I taped up a LR trailer target and got the Disco to recognise the trailer and complete the forward "training" before I ran out of space in my driveway. That then enabled the "Advanced Trailer Assist" - took a while to figure out that you can then pull up the "mode" **** another 1/2". I dared to let it back up the rig around a curve for a few feet but it's a bit too spooky for my liking as everything is blind - trailer appears about 20ft wide when you look at it in the rear-view-camera. One downside with the Airstream is that the propane tank cover, which is the ideal place to mount the target, ends up just under 3ft from the Disco camera - Manual says it needs at least 3.3 ft and the target is not recognised when taped up on the tank cover. I taped it up on the front window glass and it is recognised there, just, (unless you go over the crest of a hump and then it disappears from view and looses sync). So, ATA is probably a no-go and a more sensible investment would be big wide mirrors, a better-trained assistant and maybe a remote backup cam for the Airstream.

Jeez, I've never had to RTFM for a car so much in my life. Would be cool if the Disco could recognise a wireless backup camera though ...

 

Forgot to add, my Airstream is all-LED lighting too. Lots of them.

 

The only way to get a reliable indication of trailer connection with led lights is by adding resistors in the tail light wires on the trailer. I have a tandem boat trailer and the disco will not see it connect. I put the resistors in and the problem resolved. Apparently there's not enough resistance in the LEDs to trip the A to D converter.

 

Just to be clear, did you put in series or parallel resistors? You wrote "by adding resistors in the tail light wires". LEDs draw less current than filament bulbs, typically. That means they have higher resistance to the same 12V source - if the Disco needs to see more current to see the trailer then it ought to be a *parallel* resistor that's needed, across the LED light circuit, not in line with it. Or maybe the Disco is not current-triggered? Can you confirm how you wired your resistors? Thanks.
P.S. If I have time I'll try an experiment with different resistors on the 7-pin connector of the Disco.

 

I put a 6 ohm 50 watt resistor from each tail light/turn wire to ground (so in parallel) And to be clear the trailer lights work without the resistor, the disco just doesn't detect it and so it doesn't seem to turn on its trailering program which helps with anti sway. Otherwise I would not have done this. I got the resistors in a kit on ebay as this seems to be a common problem with led lighted trailers.

 

I had into this same problem with my wife's 2018. Autozone, Walmart, Amazon etc. sells a Sylvania LED Load Resistor 2 pack that took me about 10 minutes to install and now her Disco recognizes the trailer.