In the old days, it was very simple, there was just the aftermarket wring kit available (Bypass Kit) but now you can have the manufacturers own Vehicle Specific Kit fitted (VSK).
A VSK will integrate with the vehicle systems to activate the dash trailer warning light, deactivate parking aids and the rear fog lamps when towing, it can also initiate vehicle systems such-as the trailer stability control program, suspension settings, traction control and anti-lock braking.
The Bypass Kit is a more basic system making it ideal for older vehicles and vehicles with basic technology. The Bypass Kit is soldered in place or mechanically locked to a feed, it doesn’t integrate with any of the vehicles systems other-than to provide a synchronised lighting out-put, It is up to you to decide what features you want from your Towing Electrics. It might be the case that the car manufacturer recommends that the vehicle specific kit is fitted, vehicles that are under a manufacturer warranty may also require you to fit a VSK in order to comply with warranty conditions. Regardless what system you opted for all wring installations are guaranteed for 12 months and completed to the highest standard.