Tow bar purchased and waiting for installation. However the need in electronics module to control the trailer back lights arose. After small research it appeared that 2 types of modules exist: universal modules and vehicle model dedicated modules. Universal modules are cheap and require cutting vehicle wiring for installation. They fool the vehicle systems, that there is now trailer behind. This may lead to the improper function of stabilization system, rear lights controlling system and parking sensor module. On the other hand the dedicated modules solve one or more of these problems at the higher price and most of them do not require wiring cutting. Another research helped to choose the best among the dedicated modules. Excluding Estonia from the places of purchase due to inadequate pricing, it seems, that Volvo original TRM with wiring is priced the same or cheaper than non-original modules. And it handles all the problems, while non-original modules only part of them. Decision is obvious: I will order Volvo TRM with wiring from England, and after installation will only need to visit local Volvo dealer for programming the software.