We just got the OEM trailer hitch and wiring harness installed by the dealer this week for just over $600 CAD on our 2017. Considering the cost of the parts, it was an amount I was happy to pay to keep me from spending half a weekend day on my back under the car. I can't comment on the level of difficulty unfortunately.
I have a 2015 Cx5 and it is a 1 hour job , it needs at least 2 people and make sure you jack the 2 back tires as high as possible and please secure the vehicle very well using jack stands in both sides , it is not difficult
I installed the Draw Tite 76138 Class III hitch on my 2018 CX-5 this afternoon. Took me about an hour to get the job done. I drove the rear wheels up on my RV leveling blocks so that gave me about 3 more inches of room to work with under the car. I'm pretty sure I could of completed the install with the car just sitting on the garage floor. Since it was just me doing the work, I used a floor jack to help hold up the hitch while bolting it in. The whole process was just like the video showed on etrailer. This weekend I hope to install the Mazda wiring harness.
I installed the Draw Tite 76138 Class III hitch on my 2018 CX-5 this afternoon. Took me about an hour to get the job done. I drove the rear wheels up on my RV leveling blocks so that gave me about 3 more inches of room to work with under the car. I'm pretty sure I could of completed the install with the car just sitting on the garage floor. Since it was just me doing the work, I used a floor jack to help hold up the hitch while bolting it in. The whole process was just like the video showed on etrailer. This weekend I hope to install the Mazda wiring harness.
Which wiring harness did you get?
On the non-Mazda harnesses, you can keep the trailer wiring connection hidden in the spare tire area and remove it only when towing. It would sit flat and the hatch door would close without any issues. That's how my 2016 CX5 had it. The wiring remained hidden and was only remove & placed over the hatch and closed when needed/towing.
Which wiring harness did you get?
You could do that with oem harness if you wanted, but you may have to slip off the corrugated tube. I was worried about damaging the wire or seals on the tighter ‘17
Did you have to drill a hole in the vehicle to run the wiring?
No, there is a rubber plug in drivers side wiring harness area and it drops through there. The OEM kit comes with the 4 wires without the plastic male connector on one end. You pass them through the hole where the rubber plugs was, slip the grommet on, then pop the 4 wires into the plastic plug (metal connectors already on wires) then you just push that plastic male plug into the female plug on the module.
The biggest warning in the docs is to keep the wire away from the muffler (5cm min) I was able to route my wire on the rear side of the hitch - between the bumper and the hitch. The OEM hitch is designed differently. It tucks up higher and it looks like they had to pick a different wiring path.