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Discussion Starter #1
I first posted in Anything Sienna. This seems to be the more relevant thread. Thanks.

Greetings everyone! First, my question, then the back history.

I have a new to me '05 Sienna LE. Is the wiring harness with connector already in place at the driver's seat? I want to replace the manual seat (which controls my wife has difficulty with) with a salvage yard power seat. Can this be done easily if the cable and connector are not there?
Secondary question: Will replacing the manual seat with the power seat affect the airbag function? Thanks for any help on this.

LOL! I counted up last night: I have owned 8, yes, count them, 8 Caravans since 1995. None new. All purchased at least 7 years old. Only the first one I had to trash--an '89 turbo 4. The rest I have repaired and driven for a number of years. My latest that I repaired I purchased for $200.00. Haha it went from AWD to FWD and works great now. Needless to say, I have become acquainted with this vehicle and know what it takes to make them go.

I am getting older. It was time for something more reliable that hopefully will give us many years of fairly trouble-free service. My new to me '05 Sienna is a salvage title. It was caught in a mighty hailstorm. Only 127K miles. Only surface damage. I have the dealer records (found online) up to the point of damage. Importantly, the timing belt was changed at 88K (sadly, not the water pump or seals!) and other misc parts. Regular oil changes, etc. I think it was worth the money I paid for it.

Right when we received it, I noticed a grinding in sync with the wheel rotation. Searched online and thought maybe the carrier bearing on the right drive axle. I have some money but not the time and took to a local, trusted mechanic. Up on the rack and in gear showed that the right axle and bearing were fine. The problem was the left wheel bearing. A disappointment with so few miles. Since the axle was leaking some, we decided to change that out since it was easy to do. Ouch! $700.00 + with most of the time trying to remove the bad bearing. He charged me every hour he spent working on that. I told my wife, "This is why I do all the repairs!" We got new tires and, apparently, a third new windshield (this time with defroster).

Anyway, I have been all over the van taking care of the neglected things many owners don't bother with--broken hinge, loose screws, door lubrication. I am in New Mexico, and our vehicles just do not rust. This vehicle is from Colorado and it is clean underneath. We're hoping we got a keeper. Being the LE trim, its got aluminum wheels, rear discs, power windows and mirrors (but not doors), alarm system and 3 zone AC but nothing else. We really need those power seats. Can it be done?

This forum is great. Anything you all have to share with me to keep this one going will be greatly appreciated
 

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Welcome!

IIRC, the power seat was an upgrade package option on the LE when I bought my 2008. There's no integration into the body ecu (seat memory), so it's pretty much a stand-alone component.

Other stuff connected to the seat that you'll find connectors for: Presence detection for the airbag system, the side airbag itself, the seatbelt detection ckt, etc. Careful with the yellow harnesses! Blowing off an airbag is not the goal here.

If you are lucky, all LE vans will have the 30 amp connector and ground connector under the seat to route to the power seat controls. There are 5 motors (forward/backward, front cushion lift, rear cushion lift, seatback recline, lumbar), but it's all self-contained. If not, it should be a simple enough routing to bring in a fresh 30A line.

XLE vans also had heated front seats, if you want to go double deluxe!
 

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I moved one thread here and deleted the duplicate.
 

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Discussion Starter #5
Welcome!

IIRC, the power seat was an upgrade package option on the LE when I bought my 2008. There's no integration into the body ecu (seat memory), so it's pretty much a stand-alone component.

Other stuff connected to the seat that you'll find connectors for: Presence detection for the airbag system, the side airbag itself, the seatbelt detection ckt, etc. Careful with the yellow harnesses! Blowing off an airbag is not the goal here.

If you are lucky, all LE vans will have the 30 amp connector and ground connector under the seat to route to the power seat controls. There are 5 motors (forward/backward, front cushion lift, rear cushion lift, seatback recline, lumbar), but it's all self-contained. If not, it should be a simple enough routing to bring in a fresh 30A line.

XLE vans also had heated front seats, if you want to go double deluxe!
Thanks fibber2. Just the info I was after. I will start searching for the power seat at area salvage yards. Online of course. All the yards are at least 2 hour drives from here.

If I understand correctly, disconnecting ground and letting it set for 15 minutes or so should help keep me safe with airbag issues.

I will dig under the carpet to see if I can find a power connector for the seat. It looks like only 4 bolts holds the seat in.
 

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Discussion Starter #6 (Edited)
OK. Here's another question. Gen 2 Siennas run from '04 to '10. Will the seats from say an '04 to '07 or later be a direct replacement for my '05?
 

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Discussion Starter #8 (Edited)
Well, here's the story about the seats. Let me say up front it was a lot of work. Mostly chasing down wiring harness.details. I found the info at this site to be excellent: https://www.ludicrous-speed.com/automotive/toyota/sienna/2005/

The search for seats led me to call all the salvage yards in El Paso. I struck out after spending all morning calling. Tucson was next. But first, I wanted to see if any were available on eBay. There were. In fact these seats were in Las Cruces which was even closer. And I had a Dr's appointment there the following week.

He had like 8 or so 2nd gen Siennas. The guy said that '07 and up had different seat connectors. Turns out it didn't matter. I'll explain later. Also, one of the vans had a receiver hitch and tail light adapter. I needed those as well.

There was an '05 with beige power seats. Mine is gray. I took them anyway. We cut the cable under the seat.

Installation: What took a long time was studying the wiring junctions, and connectors. The power seat 30A fuse is in place. The diagrams show 12V power leaving down each floor wiring harness. I first checked under the passenger seat to see if there was a purple wire. No. Then I checked for the black connector under the passenger kick panel. No connector. Then I looked at the junction connectors at the cabin fuse box. Sure enough, a purple wire. But there should be two from 2 different junction connectors. The wiring diagram says that purple wire should be found behind the glove box at a junction connector. My telescoping mirror showed that to be true. There is power at the pin but no corresponding female connector with a purple wire. I don't have any of those connectors that fit in the junction box. I'm sorry I didn't cut that junction connector from the junked van. That would have been very helpful!

Oh well. Back at the junction at the fuse box, I cut the purple wire and tapped into it. Soldered it together. Then I ran that wire and a ground to the driver's seat. There is a convenient ground terminal at the driver's kick plate.

For the connections under the seats, I pored over the diagram to make sure I understood where everything was. Even though the power seat wiring harness had an airbag connector, I ignored it and just used the original connection. Those were the same. The power seat and seat heaters are all on the same connector. I didn't look to see if the seat heater wiring was there as it would require the switches in the dash which I did not get at the salvage yard.. I will live without heaters. The other connector is related to the sensors under the seat. The wiring diagram shows that the wire colors are identical but Toyota chose to use a completely different connector for power seats than the one without power seats. Six wires on the passenger side. I cut that connector off, and one at a time, I reconnected each colored wire with the new power seat harness. I did this in case the new power seat did not work for some reason. I can always reinstall the original seats without hassle.

Power for the passenger seat came from the driver's seat connector. I ran the 2 wires under other cabling and duct work.to the passenger seat. There I soldered the wires to the power seat harness.

Before installing the leather seats, I cleaned them well with a mixture of distilled water and Woolite then I use a leather cleaner and conditioner. They were pretty dark and grimy but they cleaned up nicely. Unfortunately, the table on the driver's seat cannot be transferred to the power seat. It does not have the right kind of bracket. I may look for a console.

Well, I am happy to report that all the power functions work on the seats. However, when I started up the engine, the airbag light began flashing. I looked online and folks were having trouble with the connector under the seat. I double checked each seat. Sure enough, the driver's airbag connector I had used was the wrong one.

On an unrelated note, after taking a test drive with my new seats, it appears my AC compressor had just died.

Thanks again to everyone for the help and input. If anyone wants to tackle this job, please contact me and I will share what I know about the connectors and such.
 

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Nice work sorting all this out!

You know, I actually want to go the other way on my 2017 LE, take out the stupid power seat and put in a manual adjust model. Probably a direct bolt-in, but do I have to change connectors too?

Anybody want to trade seats? We must have the gray interior on the white car. Eugene/Springfield, Oregon.
 
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