Tow Bar Electrics Freelander 2

Recently had our FL2 2010 TD4 HSE tow bar wired in. WE bought it 4 years ago and the tow bar was never wired in. The electrics work when ignition is on (1st stage) but once engine is started the electrics wont work. The garage plugged it into a diagnostic machine and was online with LR . The ECU would download the program nut not enable it. The mechanic had said that part of the wiring was missing, a plug in box module. which he then wired in himself. Could this be why the ECU wont enable the tow bar? Do we need to go to an auto electrician or get a whole new LR compatable wiring kit? Thanks in advance for any help.

The Freelander 2 up to late 2011 used a towing module to control the trailer lights. It get mounted behind the LH boot trim.
It's connected to the low speed data bus, and converts the lightning digital requirements in to actual power to make the trailer lights work. From memory, the towing module is able to operate the trailer lights without any programming at all. However, the programming allows the communication back to the CJB, so things like the trailer telltale on the dash flashes, and the rear PDC and fog lights don't activate when the trailer is plugged in. It's the CJB that needs programming, so it knows the trailer module is fitted, not the trailer module itself, although the module can have later software loaded if needed.
Oh and the trailer module doesn't power the brake lights, as those are powered directly from the CJB, the module simply passes the brake light feed straight through to the trailer harness.
Here's the trailer module in mine.