Since I picked up my CX-3 with a tow bar, the location of the wiring socket has bugged me. For those that don't know, the wiring socket is located in the boot and when connecting a trailer you have to have the cable hanging over the boot lip. This to me feels like an afterthought for a car that is otherwise so well designed. As someone who does a lot of towing this is something I decided to resolve and today I relocated the trailer wiring socket under the bumper so that it's now accessible from the exterior of the car without having to have the cable running over the boot lip
I put together a quick tutorial for anyone that might like to do the same thing. This wasn't a simple process and probably took me 4-5 hours all up. Albeit, a lot of that time was spent exploring how various parts disassembled and working out where I could run the wires. Forging this, the steps below would still probably take the better part of two hours.
Let me know if anyone has any questions or wants to clarify anything!
I started by removing the boot floor, spare tire and other equipment that is stored under the carpet of the boot. Note the existing location of the wiring socket
There are two plastic pins that hold the trim in place over the boot lip. A small flat head screwdriver removes these, then the trim can be lifted directly up
I wanted to gain access behind the side wall of the boot - where the cable was coming from. Under the tie down points are two 10mm hex nuts that hold the side wall in place
I couldn't figure out how to release the rest of this panel (looks like the seats might have to be removed first) but it was flexible enough to give me access to the area I needed
The boot area is extremely well sealed. Each seam is fully welded and then a sealant applied. After much exploration the only access to the under area of the car I could find was this hole again sealed with a rubber grommet. Here I used a cable puller and fed it through the hole so that I could figure out exactly where the cable would end up
There was no way the flat pin trailer socket would fit through the hole so it had to go. Two screws on the outside of the socket release the top cover, then each wire can be released individually. (Even if I wasn't doing a guide I still would have taken a photo of this step and recommend you do too as a reference for replacing the wires later)
With the plug removed I taped the wires together to keep them clean and make it easier to feed through the narrow spaces
I cut a small slit in the rubber grommet and pushed the wire through. Though not watertight it ended up making a pretty decent seal
Underneath the rear of the vehicle there are two plastic supports that mount from the body of the vehicle to the bottom of the bumper. I decided this was the best place to locate the socket to keep it out of sight but still accessible. A plastic pin holds the support to the bumper and another 10mm hex bolt joins the support to the vehicle. I removed both to make mounting easier
I used a sharp screw to mark the location of the socket and then drilled holes to fit bolts through
I then rewired the socket (check and double check the location of each wire!) and mounted the socket to the bumper support
With the socket in place, replacing the bolt that joins the support to the body of the vehicle was a simple process as was reconnecting the bumper with the plastic pin
Finally, I used a couple of cable ties to keep the wire supported and out of the way of the exhaust
The mount is completely invisible from the rear of the vehicle!
This for me is a far more practical location for the trailer wiring socket. Having the wire extending over the boot lip caused too many issues where the wire would get caught or the boot wouldn't close properly, not to mention the socket rattled against the paint job. Hopefully this helps someone else who might like to do the same!