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Hi everyone, this is my first post.

Question: I am looking at an '09 LE. The option list includes a "TOWING PREP PKG (TO)" AND A "DPS HITCH W/WIRE HARNESS & BALL MOUNT (DH-N)" Can anyone tell me exactly what those options are and do I need both? I am going to tow an '09 Starcraft 2106 popup.

Thanks,

David
 

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Hi David!

The "TOWING PREP PKG (TO)" is the option that gives the Sienna the capacity to tow up to 3500 lbs. of trailer; without it the van is only rated to tow 1200 lbs. This option adds an external engine oil cooler (not an auxiliary transmission cooler) to the 3.5L engine. Do you need it? The 2106 has a GVWR of 2090 lbs. (from www.starcraftrv.com), so according to Toyota you need this option. There has been some discussion of whether this is really necessary to tow over 1200 lbs., but that's another topic. For the cost of the option (was $220 in 2008 but I hear it has gone down some) I would get it if possible. For lots more info see this thread: http://siennachat.com/forum/index.php/topic,116.0.html.

The "DPS HITCH W/WIRE HARNESS & BALL MOUNT (DH-N)" is the option that installs the Toyota OEM Class II receiver hitch and wiring to a flat-4 connector (for stop lights and turn signals). If your 2106 has electric brakes (highly recommended, Toyota requires trailer brakes on anything over 1000 lbs.), you will still need to install a brake controller and additional wiring to convert to a 7-pin receptacle. Also, the Class II receiver has a 1-1/4" opening vs. a 2" opening of the available aftermarket Class III hitches. The OEM Class II receiver is not rated for a Weight Distributing Hitch (WDH); all of the Class III receivers are. Whether the Starcraft can handle a WDH (not all trailers have a strong enough frame for the forces of a WDH), and whether you will need a WDH (maybe not, that's a fairly light popup) or will want a WDH (maybe so, the Sienna's rear suspension is pretty soft and easily sags under a load) should be the topic of another thread ;). So do you need this option? Not necessarily, aftermarket parts can be installed (by yourself or by a hitch shop). But if you want the option of using WDH (or have something like a bike rack that fits a 2" receiver) then you don't want to pay for this option; Then again, if you don't want/need the Class III receiver, and prefer the slightly less bulky Class II, the OEM Class II is the only one available for the Sienna. For info on what the "DPS" part of the OEM receiver is, see this thread: http://siennachat.com/forum/index.php/topic,496.0.html.
 

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My question is what is the "wire harness"? I searched everywhere around the rear end of the vehicle, underneath, all the compartments, there is nothing there re trailer wiring.

It has a Uhaul hitch, but Uhaul has told me they can't do trailer wiring on this vehicle, that it requires a Toyota part available only from Toyota.
 

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You are responding to a 11 year old thread.... What year van, did you buy it new (sounds like no.).

The Sienna does not have a single point plug for adding a trailer wiring harness. Even though it might appear on the window sticker, I don't believe this was ever an actual factory build option. It was added by either the Distributor or the Dealership.

You have to pick up signals at both taillights (so you need to pull panel on both sides), and you will need a power home run back to the battery to run it all (if you do it right, with a buffer module). Many installs end on the passengers side interior, with the trailer extension wire stuffed into the jack compartment. You uncoil it and run it out the rear door (carefully pull the rear lid down over the wire running over the rubber seal).

Some have added an extension and found (or drilled) a spot to run it out under the vehicle to the hitch area.
 

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You are responding to a 11 year old thread.... What year van, did you buy it new (sounds like no.).
dabunting's post in this thread makes more sense after reading a thread he started at trailer lights harness where is it?

If a "trailer light harness" is listed on the window sticker of the 2008 Sienna he bought, then it probably would have been installed at the "port" and shown in the feature list if he looked up the VIN at Vehicle Specification | Toyota Owners . All Sienna go through a port process even thought they are manufactured in the U.S. It is during the port process that accessories like trailer light harnesses and receiver hitches (and mudflaps, floor mats, etc.) are installed.

But it doesn't make since that his 2008 Sienna would have a Uhaul hitch if it had a "factory installed" trailer light harness since (my understanding) it was not possible to get a port installed trailer light harness without a port installed receiver hitch. I suppose it is possible that the original port installed hitch got damaged and was replaced with a Uhaul hitch by the previous owner.

Post your VIN here and we can help you confirm what, if any, towing equipment was originally installed on your 2008 Sienna at the port.

And I suppose it is possible that a port installed trailer light harness was removed, e.g. during repair of serious rear end damage.
 

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Thanks, Geezer!

Thinking back, two situations come to mind:

1) The Dual Port hitch system (trailer hitch / cargo box carrier) was a 1.25" system, not a 2" receiver. Some who had the Toyota units installed initially might have swapped them out for the more versatile larger unit.

2) Some models had a weight discrepancy in their factory door jam labeling. I think this was an early Gen-III issue but there might have been some Gen-II vans caught up in this debacle. When owners took their vans into dealers with the recall letter to get a revised door label, they were also inadvertently authorizing the dealerships to remove their tow hitches! Lots of anger over that one.....
 
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Another guy replied that etrailer sells a wiring harness for it, less $ than one also available from Toyota. I found it and ordered it ($53). You open up and unplug each taillight connector, this "T adapter" assembly with solid state controller accepts those plugs and gives you another plug to put in each taillight, and has a third cable ending in the flat 4-connector trailer connector. Also available ($12) a bracket to mount the flat trailer connector if you want to do that. Looks like the good solution. I'm really crashed for time, but installing this will take much less time than round trip to Toyota dealer! Thank you all most sincerely for your help!!!
 

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If done right, it is still going to require a fresh 12v line of at least 10 amps to power the trailer lights. These modules act as an interface to only use the Sienna taillights as a trigger, and then get fresh power for the trailer from a run back to the battery. The stock Sienna circuits were not intended to carry an additional external load. Just a heads up that there will be a little bit more work to do.....
 
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Also available ($12) a bracket to mount the flat trailer connector if you want to do that. Looks like the good solution.
I found the Hopkins 48595 to be a clean (and cheap! - $4) solution for installing a 4-flat connector on the underside of the bumper cover of my 2014 Sienna. Installing it required drilling two small holes in the underside of the bumper cover. IIRC, I could have installed the 4-flat connector that's part of my trailer light harness in the Hopkins bracket but I bought a Hopkins 4-way extension cable for maximum flexibility, e.g. if the external connector ever got damaged, I could unplug the extension cable from the trailer light harness connector and then string the trailer light harness connector cable out the hatch door of the Sienna. I hate closing the hatch door on a trailer light harness cable since the rubber door gasket contains a sensor and I don't want to think about what would happen if the trailer light harness cable ever got entangled in the power door latch that wrenches the door shut.

Here's what the Hopkins bracket and the extension cable I used look like.

Hopkins 4 Flat Mounting Bracket - view from angle.jpg Hopkins 4 Flat Mounting Bracket - view from behind.jpg Hopkins 4 Flat Mounting Bracket #48595.jpg Hopkins Connector Set #48215 to adapt Curt #56106.jpg

Edit: I forgot to mention that I had to wrap the connector with electrical tape so that it would fit firmly in the Hopkins bracket and not slide around. That might not be necessary with other brands. I thought it was odd that a Hopkins brand connector didn't fit firmly inside a Hopkins bracket without making this minor modification.
 
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