Quote Originally Posted by BMKal View Post
You don’t need an adapter. Everything other than the green trailer light on the dash works perfectly with or without the adapter and the green flashing light.

I have two trailers, both with all LED lights - one has resistors wired into the indicator circuits and the green light on the dash flashes when the indicators are on. The other trailer doesn’t have resistors wired up yet and the green light on the dash doesn’t work. Other than that, there is no difference in towing the two trailers.
Sorry, but that's incorrect - at least for the Discovery Sport which is what this question is all about.

If you don't see the green trailer symbol flashing when you indicate, then the towing program has not been activated on the DS. Yes the trailer will still follow you around, the brakes and lights will work, but none of the special towing features will be on.

If you don't believe me then try this very simple test.

Hook up a trailer with LED lights and no resistors - the green trailer symbol won't light when you indicate, and the rear fog lamps and rear parking warning beeper work as per normal.

Then attach a trailer with incandescent globes, or LED globes and resistors. The green symbol will now flash when you indicate, and your rear fog lights will no longer work, and you rear parking sensors are de-activated. This shows the DS now knows a trailer is attached and has activated it's towing features. The rear fog lamps are de-activated so they don't distract you by lighting up the trailer, and the reversing beeper is turned off so you don't get a constant alarm every time you select reverse because it's detecting the trailer behind you! These are the most obvious signs that the DS has activated its towing program, but other, less obvious things will have changed which are more about safety than just convenience - specifically trailer stability assist.

Trailer Stability Assist.jpg

So, in summary - if the green trailer symbol on your instrument display doesn't flash with your indicators, the DS doesn't know a trailer is attached and won't have activated its advanced towing features. Does this mean you will immediately crash and burn? No! But as you've paid for a car that has all these fancy electronics to make towing more convenient and safer, you might as well use them when all it takes is the installation of a couple of resistors costing about thirty bucks!

Load resistors 1.jpg