2005 Sienna Tow Hitch & Tow Capacity

I just purchased a used 2005 Sienna and have a couple of questions.

1. I need to install a trailer hitch to pull my boat which weighs in the neighborhood of 1,500 lbs including boat, motor, trailer, and gear. (I may also have the occasional need to pull another trailer up to 2,000 but never any more than that.)

I read that many Sienna owners experience scraping of the hitch due to how low the Sienna hitch sits. (apparently due to the deep well for the 3rd row seating storage.) I just traded in my Chevrolet Venture minivan (98) which I used to pull the same boat and it never scraped. (although it didn't have stowable seat storage.) That hitch had the 1 1/4 solid metal tube but I don't recall if it was rated at 2,000 or 3,500 lbs. (The hitch was already on the van when I bought it and the tube I got from Uhaul.)

I was hoping to get some feedback from you as to what brand of hitch you used and if you have the scraping problem. (Also how much total weight/tongue weight you tow.) I read another post on another site that indicated the Toyota hitch gave better clearance than the aftermarket options. Anyone know if that is true?

2. I'm a little confused as to how much weight the Sienna will tow. The manual says 2,000 standard and 3,500 with the towing package. I read on the net that all Siennas in the 05 year had the towing package included. ??? Is the towing package simply transmission/radiator coolers only and has nothing to do with a beefed up frame to hold the weight? Any idea how I can tell if I have the towing package or not? (I have no idea what a transmission or radiator cooler looks like.) I'm really not too concerned even if I only have the 2,000 capacity because I won't be pulling over that amount and I don't pull very often and when I do, I don't go more than about 100 miles to the lake. Still, I'd prefer not to cut it that close and would feel more comfortable with the 3,500 limit. How can I verify what I have?

3. I watched a video on-line that showed the install procedure for the wiring harness on a Sienna. (04-10 class) They showed the wiring just hanging out of the back of the van instead of coming from underneath the bumper like all of my past vehicles. That seems very cheesy to me to run the wire out the van and then close the door on the wiring. Is there an easy way to route the wiring under the bumper to avoid the ugly mess of keeping it inside the van?

4. I have the JBL speaker on the driver side in the rear instead of an access panel. In the wiring install video, the guy opens up a panel to help get to the wiring. Am I going to have problems with this since I don't have an access panel and have a speaker instead?

Any insigh on any or all of the above would be appreciated. (photos of your hitch install would be a nice bonus also) Thank you.

I can't answer all your questions, but I'll do what I can.

Trailer Life magazine puts out a great annual towing guide that summarizes every vehicle rated to tow at least 2,000 lbs. I believe you are correct in that all 2005 Siennas are equipped with the towing package and rated at 3,500 lbs. I don't know if that includes the hitch and external tranny oil cooler (some just increase the oil capacity and run it through the radiator cooler). If you do have a separate cooler, it should be mounted in front of the A/C condenser, either a book sized radiator or long and rectangular like a big stack of Club crackers. It could also be mounted behind the air dam.

For that weight, you should have a Class II hitch with the 1- to 1-1/2" square tube receiver. Make sure all the receiver parts are rated to pull what you intend to and more. I don't have info on Toyota versus aftermarket clearance issues.

The wiring routing may have to do with where the main harnesses run from front to back. But I would first check to see if there isn't a wiring harness already tucked in behind the rear stop lamp or in behind that rear speaker. On some towing equipped cars, there will be a 4-wire connector just before the rear lights that you disconnect and then insert a trailer adapter harness in between. You can then run the adapter down through the rear body and out under the rear bumper. Same can be done if it is located behind the speaker...all holes eventually lead to the outside.

Let us know how it goes. Good luck!

1. The 2005 Sienna is rated for 3500 lbs towing. The 2005's supposedly have the towing package across the board. Regardless, I added a separate transmission cooler (fairly trivial job).

2. 2nd gen Sienna's and later sit LOW and have relatively soft suspension. I use a 2" receiver hitch, with a 4" rise tongue. A set of Firestone airbags helped immeasureably for towing when the van is loaded. Even so, dragging the hitch is fairly common when crossing curbs, yards and such.

3. Towing a 12' tandem flatbed (about 2k lbs with cargo) was smooth and hardly effected mileage at highway speed. Towing a 5x10 enclosed (taller than van) cut the mileage in half and had it searching for gears. A severe headwind had me ducking off the highway and looking for quieter backroads.

4. The wiring harness mounts in the jack stowage area in the right rear. Easy access to the vehicle's wiring and you need a conversion box. The trailer harness gets rolled up and stowed in there and poked out the rear door weatherstrip when needed. It's actually a GOOD thing and keeps the harness and wires clean and undamaged and prevents corrosion.

5. Couple of notes about the Sienna.
A. It's known to have radiator leaks at higher mileage. Luckily it's usually self sealing, but pay attention pre and post trip.
B. The 3.3 using a timing BELT. If you're regularly towing, make sure you change it between 80k and 100k. There are kits that supply seals, gaskets and a new water pump, go this route. Labor is $350-500.

So, it'll tow and do it fairly well even up to near it's capacity. Still, it's not a TRUCK with the suspension, rear end, torque/hp, and ground clearance to make it trivial. Tow wisely. Stabilizers at regular 3000lbs would be a good idea as would electric brakes.