The two plug and play trailer wiring harnesses available for our Cruze are $50+ so I decided to write this how to article on how I wired mine up for under $20!
You first need a taillight converter kit because the Cruze has independent brake and turn lights. I used the Hopkins brand #48895 available here:
Amazon.com: Hopkins 48895 Incandescent/LED Taillight Converter: Automotive
Step one- In the trunk you need to gain access to the left and right side taillight pigtails located behind the carpeting, the video here will show you how to do that
Step two- Once you can see the taillight connector on the left side disconnect it by pushing the little tab in and pulling it out. It will look like this.
Step three- Cut back 4 inches of the electrical tape on the harness to expose the wires.
Step four- Using tapping crimp connectors (or soldering) connect wires from the converter to the vehicle wires.
Brown wire - Purple (taillight)
Yellow wire - Blue/ white (left turn)
Red wire - Gray/ yellow (brake light)
Do not worry about the long green wire or the white wire yet.
Should look similar to this when its all crimped.
And this after taping and plugging the harness back in.
Step five- Mount the converter to the car with a zip-tie or 3M tape and screw the white wire (ground) to the car with a self-tapping screw.
Step six- Run the green wire (right turn) along the trunk threshold to the right side of the vehicle and crimp that wire to the yellow wire on the taillight side of the harness. The vehicle pigtail side has a much thicker sheathing and you could tap that side of the harness but I believe you would risk the integrity of the harness so I decided to tap the taillight side. It shouldn't matter unless you plan on swapping taillights.
Step seven- Put everything back together in the opposite order you took it apart and run the new trailer wire pigtail either through a grommet and up and under the trunk to the hitch receiver or just keep it in the trunk tucked under the carpet until needed. I chose the latter so that the harness was protected from the harsh Michigan winters.
Disclaimer - I take NO responsibility to any damage you cause to your vehicle by following these instructions. That being said, I have hooked up multiple trailers and the lights on the trailer work great and NO issues whatsoever on the car itself either.