Installation of Tow Ready T-One Vehicle Wiring Harness 4-pole # 118255 on a 2012 Lexus RX450H

Updated 08/21/2013 | Published 08/17/2013

Question:

A little confused. I see the white rectantagular plug here and I see one under my RX450h on right side tail lights lower. I assume this plugs into it. However i see no other end to this t connector. I do have a gray plug under the bumper. Does that go liveinch once i add the t connector and then I use the other cable that converts that grey plug to a flat pin? My grey plug under left side of bumper is dead but wiring seems to go into the car and into some black box. thx

asked by: Dez

Expert Reply:

To install the Tow Ready T-One Vehicle Wiring Harness 4-pole # 118255 on a your 2012 Lexus RX 450H, the white plug that has a small black box attached to it plugs in to the vehicle wiring harness. This attachment point is located in the rear cargo area of your vehicle, and is on the passengers side. Then the gray plug that has the trailer 4-pole at one end will plug into the connection point underneath your vehicle. There is also a 10 amp mini-fuse included in this kit and that will have to be installed in the vehicle fuse box.

For trailers with a 4-pole wiring system the brake and turn signals are combined in one red taillight, and on your Lexus there are separate taillights consisting of a red for brake and amber for turn signals. The small black box that is included in the wiring kit is a converter and it combines the vehicle input signals and converts the signal so that the taillights on the trailer functions properly.

The plug that is installed in the vehicle cargo area only has one end. The way this plug is configured it takes the signal out of the vehicle and routes it through the converter and then reconnects to the vehicle to send the signal to the second connection point that is located under the vehicle bumper.

Once you have installed the white plug into the vehicle cargo area then connect the trailer 4-pole connection with a gray plug into a connector located underneath your vehicle behind the bumper.

Included with this installation kit is a 10 amp mini-fuse that may need to be installed in the fuse panel of your vehicle. Specifically this 10 amp fuse is assigned to the position lights, tail lights, license plate lights, and towing converter. I have checked an on-line version of your owners manual (section 4.3) and it looks like this mini-fuse would be installed in position 21 of the fuse panel that is located near the emergency brake pedal. I found this information in an on-line version of an owners manual for a 2012 Lexus RX 450H please confirm this information with your copy.

expert reply by: Rachael H