Troubleshooting Wiring Harness Install on 2003 Lexus RX 300

Updated 03/20/2018 | Published 03/19/2018

Question:

We purchased a trailer hitch and vehicle-specific wiring harness for a 2003 Lexus RX 300. The hitch and harness went in easy. The trailer lights did not work and it took a while to discover we reversed the plug under the fuel tank. We turned the plug around and installed new fuses one below the trailer appears dead also. Nothing seems to work. We must have sent a spurious voltage back through the system into another component. There is also a light on the dash indicating rear lights have failed. Any ideas?

asked by: Jeffrey M

Helpful Expert Reply:

The T-One Vehicle Wiring Harness for Factory Tow Package # 118245 is a plug-in for a 2003 Lexus RX 300 and would only require you to place a 20 amp fuse like shown in the accompanying photo and linked video to the install of this part on an '03 RX 300. Uninstall the connector and see if the light on the dash goes off. If so, try re-installing it by following the same steps as in the video. If the light remains on I recommend having your vehicle looked at by a mechanic to determine the issue because a wiring harness that plugs into the factory tow package port should not cause your taillights to fail.

expert reply by: Kyle S