2010 Rx 350 Fwd Trailer Light Connection

2010 T-Rex · December 17, 2010

Many 2010 RX 350s did not come with the trailer tow kit and I, as well as other owners, have had difficulty in finding the proper parts to route power to the existing trailer hitch connector (under the bumper). I finally found a solution and it entails purchasing part number PT219-48101-TC and installing it in the right rear quadrant of the vehicle. I have attached basic installation instructions with pictures for anyone that wishes to attempt to install the converter. Note the cost is a bit more at than the after market solutions available, but it does fit right in place and matches with existing connectors so no cutting of wires is required. The converter cost is around US$90 - US$115 . Good luck and be patient!

Adding RX Tow Converter for trailer lights on FWD RX 350.pdf

Fidzio · November 15, 2013

It took me a week to find this post, and 2010 T-Rex did an excellent job in putting together the instructions. I installed the converter and the extension harness on a 2012 AWD RX350 with NO trailer package installed, and it works great!

I took a few shortcuts during the installation (didn't remove the cover in step 3 and just gently pulled the wallboard away from the side to install the converter in step 7) but otherwise installation was a breeze!

I bought the 118252 wiring extension harness (for $16) to make the connection from the bumper connector to a flat 4 pin trailer plug.

Total cost of parts to make the wiring work on a RX350 without a trailer package was $122 ($106 for the converter from a local Lexus dealer, and $16 for the extension harness part 118252 http://www.etrailer.com/Custom-Fit-Vehicle-Wiring/Lexus/RX+350/2012/118252.html?vehicleid=20121174036)

Thanks again to 2010 T-Rex for the great instructions!

GolfRx · January 5, 2014

Here's another solution that I have not seen anyone mention here yet regarding trailer lights on the RX 350. I too have a RX 350 AWD and installed the Curt hitch myself and the plug and play wiring (without the converter). Although the trailer lights worked when tested, what I found in use was the running lights went out after about 3-5 minutes. The stop, turn and emergency would work fine. I had to use my emergency flashers to get to the lake the other morning early when this first happened.

But what I ended up trying, and it appears to be working fine to GREATLY reduce the load from the trailer lights, is to switch to LED bulbs. I have two 1157s low on the trailer and two high on loading guide posts that don't get wet. I have 4 side marker lights (two 168 bayonet and two 1895's). Total incandescent load of these 8 lights was 126 watts or about 3.3 amps.

Same number of LEDs reduced my load to about 14 wattts or about 0.32 amps. A SIGNIFICANT load reduction. I had all 8 LED lights on for about 30 minutes before the running lights went out.

Since my lower lights do get submerged when launching the boat AND LEDs are not suppose to get wet, I'm going to only run with the high lights and marker lights. This will further reduce overall load to 0.24 amps. My garage test showed that two 1157 and two marker lights on for over 60 minutes and all are still on. That's good enough for me to get to my lakes in the early morning hours and home late in the day.

In my research I found that LED bulbs for vehicles are very abundant, all base styles and colors, and not that expensive. Depending on how many LEDs you want, more than 180 degree field of view, and there are some that you can get wet but they are about $30 each. The one's I purchased were $11 for two 1157s with 360 degree lighting; $6 for two 1157 180 degree lighting (for the low lights); $4 for two amber marker lights; and $6 for two red marker lights.

Read up on these and you will find they recommend using red LED behind a red lens as a white LED will have most of the red spectrum blocked by the red lens. Red LEDs do provide a nice, bright red color behind the lens. Got the LEDs on eBay and shipping was free on all these; each was from a different vendor. I have $27 total invested in all these LEDs and am really only using $15 of them since I won't run with the lower lights as LED. They will just be dark as incandescent in just those cause the running lights to go out within 5 minutes.

Just another point of view on this. Saved me the $$$ for the converter or rewiring my car with a converter harness. Which, by the way, I had a converter on my CRV catch fire after about 10 years of use. I had this converter behind the side wall so I had to pry it off quickly to extinguish it before my vehicle caught fire. I don't ever want to hide a converter behind the wall again.