Best 4-Pole Wiring Harness for 2018 Lexus RX 350 with Factory Towing Package

Question:

Our RX350 supposedly has the factory tow package wiring prep. How do I know for sure and what item do I need to get?

asked by: Cassandra

Expert Reply:

The 2018 Lexus RX 350 with the factory tow package wiring prep will have a connection point designed to match the plug on parts # 118252, # 56083 and # HM11141945. Each of these three similar items will work with the factory tow package that has a square connector to mate with the one shown in the included photo.

Of these three products I recommend the Tekonsha # 118252 because we find their electrical items to be the most reliable of all those we offer.

Please refer to the included installation video for part # 118252 to see the connection point which is under the rear of the vehicle on the driver's side. This is shown at the 1:00-minute mark. You will want to use dielectric grease # 11755 at the time of installation to protect the electrical contacts from corrosion from moisture or trapped dirt. Zip ties like # DW05724-10 will help you to neatly dress the harness to keep it secure and out of harm's way.

This 4-pole wiring provides basic stop/turn/tail lighting signals for the trailer but it does not include the additional circuits needed for functions such as 12V auxiliary power, trailer brake power or reverse lights on trailers that have them. You can easily upgrade the flat 4-pole wiring to the 7-way blade type that includes all three of these additional circuits. I linked a photo of a 7-way vehicle socket that shows how all of the circuits are configured.

Once you install the 4-pole kit # 118252 all you need to upgrade to the 7-way is our all-inclusive 7-way install kit # ETBC7. This has all the parts you need to complete the installation and to have a fully-functioning 7-way trailer connector. An article and video are included to assist your install.