tdott

Has anyone installed wiring for a trailer on a non-tow package equipped RX?

I'm installing a hitch on my RX450h AWD and i'll find out for sure soon if it has the wiring. If it does not have it, any tips on how to install the wiring needed for a trailer hookup? Anyone out there make a plug and play harness?

Clutchless

First, this has been covered before if you do a search with the term trailer. Second, if you remove the cladding under the rear and look up in the left corner you may actually have the wiring connection plug for a trailer hitch harness. Third, even if you have it, it may not work as you may need to insert a fuse and other components and this was covered in a recent thread by F250. Fourth, I think Curt, who makes a nice hitch, also has a wiring harness adapter kit that is plug and play. Take a look at www.etrailers.com

tdott

Thanks, I did search and read several threads about towing, I didn't find any answers to my specific question about wiring on a non-tow packaged rx. Many that talked about coolers and tow packaged options and backing up with load. Thanks for your tips about the fuse, i'll keep that in mind as I go to install the hitch.

Also I was actually just on etrailers.com looking for wiring options. They only list wiring packages for tow package RXs, none for non-tow packaged ones when you search. Which is why I asked what others may have done so I know what to expect if I had to do the wiring myself.

Edit: I found some more threads about installing a factory converter, would still like to hear if anyone used another method.

chas410

Hello I'm new to this site looking for the same answer on an 2015 RX350. I have installed a Curt hitch and found the connector under the cover on the drivers side. My car does not have a factory tow package. Inside on the right rear I have found a connector that a converter has to be plugged into. I have not bought the converter yet and before I do I have some other unanswered questions. I was told that in the fuse box under the hood that a 30 amp fuse needs to be installed in a spot marked , trailer lights. I have found the spot but looking at the spot where the fuse plugs in it only has a connector for 1 side of this fuse. So I can't see sticking a fuse in that spot will do any good. Other empty fuse spots are the same way. Could it be internally wired somewhere? Don't think I want to spend $100.00 + for an OEM converter until I find out. I may have to use an aftermarket converter. I sure someone else has ran into this, but I have been looking for days with no luck

Clutchless

It may be better to find a place that specializes in installing trailer hitches and wiring. I have seen a couple of such places in Southern Maryland, a more rural area outside the Washington, DC metro area.

tdott

I went ahead and got this wiring kit, I found that it was cheaper on Amazon and because I'm a prime member, shipping is super fast:
http://amzn.to/2eo76xj

Everything worked and was plug and play. My Curt hitch is installed and ready to go.

This is the hitch I got, if anyone is interested, super easy to install as others have mentioned before and it looks great.
http://amzn.to/2eo7o7f

tdott

Got lucky, looks like I have the tow package, I found the converter in the back under the taillight trim/carpet. Only needed to plug in the adapter wiring in the plug on the lower left.

Gonna return the full kit and buy just the wiring harness needed.

Clutchless

Did you test that the trailer lights worked through the factory plug? Do you have the transmission cooler vents inside the front part of the driver side front wheel fender liner? If so, that means you have the full towing package.
I think some folks have found the factory plug under the bumper, but did not have the towing package and it did not work.

F250

I'm one of those with an oddball towing equipment scenario. Not only do I have a non-functioning dealer installed factory plug, but I also have the transmission cooler WITHOUT the accompanying engine oil cooler. I've also run across one other forum member who was in the exact same position. I still have not yet confirmed whether or not I have the converter, but that is my next to-do list item on the RXh (AFTER I get a few other higher priority issues resolved on my truck).

tdott

Yes, tested and everything works correctly. There was already a fuse in mine. Yes I have the vents. I'm good to go now.

I think cars with the wiring and no converter are just prewired for it but didn't actually come with that option.

jrfiero

I think it's been determined that having the slits in the fender liner doesn't necessarily mean there is a tranny cooler.
What's this engine oil cooler that's been mentioned a couple times lately? I don't think there is one as part of the towing package.
The plug under the vehicle is factory installed, they all have them. It's the converter in front of the right taillight that's missing without the towing package.

F250

There is an engine oil cooler which mounts above the oil filter head, but not every engine has it. From what I've read, it is supposed to be a part of the tow package, but my particular vehicle has the transmission cooler but does NOT have the engine oil cooler. There is a TSB in the US where Lexus has extended a warranty period for replacing these rubber lines when they leak. Some people have replaced the lines proactively on their own nickel. Some people have been reimbursed for doing it themselves. In Canada, it is a full blown recall for replacing the rubber lines with the new hard line configuration.

Did I get all of that correct, Clutchless?

Clutchless

Pete, you are 100% correct about the oil cooler lines situation. There are photos of the lines at this Toyota Highlander forum where a member published his how to replace them tutorial. It has the same engine, but our access is a little easier. http://www.toyotanation.com/forum/12...ng-points.html

tdott

I should note that I have a 450h, I know Ive read about the oil cooler/transmission coolers, but sometimes I wasn't sure which model was being referred to. All the really mattered to me was getting the hitch installed and wiring for the trailer. Having the coolers are nice, but wouldn't really have mattered for me since I don't plan on towing alot or long distances.

I'm glad to report that my fairly short haul went really well and smoothly. I towed with a 5x9 uhual trailer with a ramp, about 60 miles each direction. Going there unloaded, I averaged 26MPG going 55-65mph on the 95. I was surprised I thought it would be worst from what I read about. Coming back my average dropped to 22.3MPG which still isn't bad with a 1200 lb load. All in all, I'm happy how it went and wouldn't hesitate to do it again.

F250

Well, I just had a couple of interesting conversations... the first with Lexus to identify my Factory/Port build details, and the second with the Lexus dealership which installed my towing hitch receiver.

Regarding the original factory build, there was no documentation to suggest that my RXh received the Tow Package (only the Comfort and Premium packages), yet there is definitely an external transmission cooler installed.

Regarding the Tow hitch receiver installation, that work did NOT include the transmission cooler, oil cooler, OR tow wiring controller -- it ONLY included the hitch receiver at the buyer's request for a bike/luggage rack. I actually spoke to the same Service Advisor who managed that ticket 6 years ago, and he says (as others have stated here and elsewhere in CL) that Lexus recommends to NOT tow with the hybrids anyway because they will run a little hotter than the conventional 3.5L engines. Now, the Sa says the hybrids run hotter, but they use the same coolant thermostats as the non-hybrids, so I can;t really see how they run hotter on an overall basis.

Consequently, the transmission cooler must have been a factory installation, but if that is the case, why in the world would the factory install an external transmission cooler and NOT install the external engine oil cooler, especially given what the SA said about the hybrids running hotter anyway??? It's a mystery we will never know, nor does it really matter very much in the end.because I'll be using my F250 diesel for my towing needs.

I thought that this investigation would bring some closure to me, but it has only left the mystery in place, but now with even more questions than I had before.