Bastorian

Hi,
I try to install trailer brake controller to my RX 350 2010 and I need to connect it to a stop light line. Where is a most convenient place to connect?
I suppose that wired diagram could help but I can't find free source to take a look.

Does anyone have experience in this?

Clutchless

Welcome to CL. Please do some searching as others have already discussed trailer wiring long ago on this forum. However, I cannot recall anyone installing a trailer brake controller, just regular wiring for lights.

If you have the tow package it should be easy as you will be prewired and the factory hook up will be easy to access.

So do you have the tow package? If you do have you had the oil cooler rubber lines replaced with the metal ones? If not get it done ASAP before they blow and you fry your engine as it spews oil all over the highway as you watch the oil light appear on the dash!

Go to etrailer.com they sell all the necessary parts and have great instructional videos to show how to install them. I just used them to help a friend install a hitch and the wiring on her Honda Pilot.

Bastorian

Hi Clutchless, thank you for recommendations and notes. Of course I've checked this forum and other resources before post it. I have no problem with hitch and standard wiring installation, moreover I set 4 to 7 pin adapter without any issue, but only the brake controller connection make me stuck.

salimshah

Pardon my ignorance .... the standard issue is dedicated trunk signals in Lexus (most Japanese imports) and the interrupted brake light as a turn signal for trailers. Then there is a issue with loading the brake light bulb current draw. I think the device you are talking about is the "brake controller".

The burden shifts to the conversion kit seller to ensure compatibility and ease of tapping into Lexus harness. I did my conversion in '99 RX and bought Lexus kit and although I had to unbutton lot of stuff, but I did not need to splice.

I would also suggest that visit UHAUL and they will have a solution for you. If it involves splicing, I would keep looking. I detest the quick connectors and splicing does not last long when the joint is outside the cabin.

Salim

afpj

I don't think many folks install brake controllers on an RX due to load capacity. I've only used one (tekonsha) for our GMC, but that's for towing over 3k lbs, where you should be using antisway setup as well. The RX is only rated for 3500 lbs Max, so kinda pushing it if you're going to tow over 3k lbs. Curious what you are towing with the RX that needs a brake controller?

salimshah

The term "controller" is confusing me.

I am still thinking of the module that converts the RX turn/brake/lights to [US] standard trailer without causing a brake fail indicator to light up. A more fancy one will have +12v.

If the "controller" is the device that applies brakes to the trailer .. then that device should be part of there trailer and hence it should be "trailer controller".

Salim

afpj

Hmmm, I was referring to the electronic gizmo you install, typically under the dashboard, that modulates the trailer's brakes, if the trailer had electrically controlled brakes. One would not typically use such a device on a vehicle only capable of towing 3500 lbs Max, but could I suppose, if a light duty trailer had electric brakes.

salimshah

The typical interface is a 4 wire connector .. and for that you would need the import interface [individual turn signal, brake, tail light -> interrupted brake, brake and tail light]. The electronic brake equipped trailer will use the brake light signal to activate the brakes if equipped.

For the module to be specific to RX350, you need plug and play connectors. The module, I used sat in the hatch.

If you want fancier [more than 4 wire] .. they are used for camper trailers .. then please do further search.

Salim

ajunk1

hello I am having same problem w my 2010 RX 350.. did you have any luck getting the break controller to adapted w the 7 pin?

Arny

try to do the same for my rx350h 2024. any advise?

TRMc

I had the same challenge when trying to install a brake controller on my 2015 450h a few months ago. The Lexus dealer was no help at all, and Uhaul couldn’t offer anything helpful either. I ended up splicing into the 4 way plug wire under the back left side that carries the brake light signal. My controller has been working well all summer.