Ditto to my 07- didnt need relay all worked just fine although in hindsight one of these
would have been a better way.
Nowhere near as complicated as they look,take ALL the load from the signalling wires that the trailer would impose,they have the indicator buzzer built in,plus you get then get the extras available.
I made use of these on my current beastie, by fitting a much neater 13pin euro socket -I now have reversing lamps on my trailer.
I used some nice thickly insulated domestic flex to hook into the offside tailight cluster-just feed it inside the rear door frame/pillar member and up and over into the nearside.
Drop your feed to the socket out of the bottom of the nearside door pillar.
Theres an earth stud/ nut handy too.
You can easily find out which wire does what by probing the light cluster multiplug with a multimeter.
Use red scotchlocks - the wires are tiny.
Use lots of coppaslip on the towbar fittings in case you want to sell it separately in the future.
Be warned though if the towbar manufacturer has given torque wrench figures ,any thread compound will make the torque wrench go haywire.
Bosal or Witter are a perfect fit.
Most will require you to cut a little piece out of the bumper-on the underneath edge -you cant see it unless someone is reversing over you...
Keep the kettle filled and have an enjoyably easy afternoon