Chrysler 300 Trailer Wiring | etrailer Guaranteed fit Chrysler 300 Trailer Wiring. Lowest price guaranteed. Thousands of customer trailer wiring reviews, expert tips and recommendation. Lowest price guaranteed, easy online ordering at etrailer or call 800-298-8924. How to Install a trailer wiring harness in a Chrysler 300 Mar 25, 2008See how to install a trailer wiring harness in a Chrysler 300. This is a necessary component since it will power the brake lights and lights on your trailer.