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2007 LE Sienna 216001 miles
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Discussion Starter #1
When I turn on AC, blows cold both sides. However, heater returns mildly hot air on drivers side and cold air on passenger side. Any help in right direction appreciated.
 

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We had a similar problem and I did a full-on investigation. The heat is controlled by blend doors that are controlled by servo motors. The motors go bad. Fortunately, the replacement part that you probably need is around $80 from eBay.

Here's the result of my study, your solution is found under the "Passenger side" section:

It's been a couple of years, but we finally resolved all of the driver/passenger heating/AC problems. It came down to the servo actuators. We had two die all at once which really caused confusion, but the sensor pads get worn out, literally scraped off. We now have a dead one for the rear heat too, but I haven't found the time to deal with that one yet.

I went on a wild goose chase trying to find replacement servos. Why? Because they all look IDENTICAL. Why pay $100+ for it when a Lexus servo, which is identical, can be had for $45. The answer is that they are not identical inside. Also, each of the servo arms are slightly different (some doglegged, some are straight) and their travel distances are different. As far as my research and experiments went, you cannot replace any of these servos with anything other than the exact part. This was an expensive lesson.

Motors: Some of the servo's had a dead motor. So if you can replace that, then you're back in business. However, I couldn't find a replacement motor.

XLE Versus All Other Models. The XLE parts are more expensive because there are more servos and they have five pins instead of three. Be careful when buying replacement servos because the XLE parts have to have the five pins.

Those #$%&^ servo arms! The servo arms are impossible to remove. They are either friction or heat welded on. You can try to remove it, but it may cause destruction of the servo axle. Why oh why did Toyota not attach them with a simple screw?

Passenger side:
The Toyota part number for this is 87106-08060. We bought a replacement on ebay for $80. So far, it's worked perfectly. Remove the glove compartment and follow these steps by user Kevaug:
It took me about 20 min from start to finish. It was so easy. NO NEED TO REMOVE DASH
1. remove the glove box
2. there is a black plastic pop rivet holding in the floor air duct, it is almost all the way to the right of the part. Just above the bar the glove box hooks latch into, pop it out with a screwdriver
3. once the rivet is loose you just pull the left side duct off the air box
4. NOW THIS IS THE HARD TIME CONSUMING PART - you must now get the floor duct out of the way by trying to push it down and completely remove it
5. Once you remove it you can see the servo as plain as day
6. with a small stubby screwdriver just remove the 3 screws
7. remove bad servo and replace with new servo and reinstall 3 screws
8. now bring the floor duct back UP, this was easier than getting it down
9. Align the vent opening with the air box mate and press to fit the connection
10. pop back in the black plastic rivet holding the floor air duct
11. replace the glove box
12. enjoy the heat and quiet (no more clicking!)

Driver side UPPER servo:
The driver side has two of these nearly identical servos. Toyota Part Number 87106-08050 (Dorman makes a version of this which is sold a lot on ebay and Amazon). Unfortunately for us, it was the other (lower) servo that died on the driver side. However, I'm listing it here just so people know the part number.

Driver side LOWER servo:
This driver side servo died on us. Toyota Part Number 87106-08070. We bought a replacement on eBay for around $100. It came with a 3D printed arm and so far it's working great. Fortunately, it is EXTREMELY simple to replace. You can do it in maybe five minutes. You don't have to remove any body panels. It's held on with three screws.

Remember, don't waste your time trying to find lower cost similar-shape replacement servos. They look identical, sure, but the guts are different. Search eBay with the part numbers shown above.

Note: We bought both of our replacement motors from eBay user bsuinc.

I'll update this once I replace the rear-heat servo at the back of the Sienna.
 

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Discussion Starter #3
Wow thanks so much for detailed research and all your time and effort. Placed order with your recommend seller on ebay.

Changing subjects... your best replacement / cover for a cracked dash? Any threads of people using covers or skins? My dash looks like Edward Sizzor hands got to it. I bought my 07 used, does toyota warranty transfer?
 

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Before you begin changing out Servo motors, I highly suggest that you do some diagnostic work first!!

Low coolant level can cause this too. When the level drops, you can get a substantial air pocket in the HVAC heater core, and greatly reduced flow. As the coolant enters the core on the drivers side, the low flow will warm the drivers side a bit, while the passengers side stays cold. There is a procedure for purging the core and restoring flow.

Mixing coolant types can cause a permanent sludge deposit in the heater core, resulting in the same low and unbalanced heat output. The clog starts on the distant side first (passenger), and works it's way towards the drivers side.

The metal core pipes are just above the gas pedal. Remove the kick panel so that you can see and feel, and check out whether those pipes are burning hot, or just luke warm, plus how different the inlet / outlet is.
 

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Discussion Starter #5
Thank you very much for the feedback. I do not hear any clicking sound. Just mild heat coming from drivers side vents. This could be a block or issue with heater system. Will do some diagnosis before doing the motor. Thanks for help.
 

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Thank you very much for the feedback. I do not hear any clicking sound. Just mild heat coming from drivers side vents. This could be a block or issue with heater system. Will do some diagnosis before doing the motor. Thanks for help.
I recommend Fibber2's approach to first ruling out a bubble/sludge in the coolant pipes. To give more context for our situation, our servo motors didn't make any clicking sound (the classic sign). Thee motors in the servo package just died (I removed them and tested them). When they first broke, they did provide heat only when the temp was set to HI. Anything below HI was frigid cold. It was all or nothing. If you open the servo's, you can see the slider tabs they use actually rubbed holes in the sensor pad, so it had a huge dead spot. It wasn't long before we lost all heat to the front, regardless of temperature setting.
 

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@jjdreese: I just wanted to complement you on your post #2. Beautifully complete!
 

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@jjdreese: I just wanted to complement you on your post #2. Beautifully complete!
Thanks. This all started when our regular shop didn't know what was wrong and I think the Toyota dealer quoted $1200 to investigate/fix the problem. Our local shop even replaced the thermostat for free and that didn't do anything. Thus began this fairly extensive investigation and I visited a lot of car parts stores.

This forum helped me focus in on the likely cause. I did try to open the servo units and repair the motors, but none of the common fixes worked. They were d.e.a.d. And I couldn't source replacement motors from anywhere. There are nearly identical servo parts for modern Lexus vehicles that only cost $49, but the guts are different. There are also very similar parts for the non-XLE and non-XL models that only have 3 pins in them (and seem to be WAY cheaper). But those won't work in the XLE or XL.

At one point, I thought of buying the cheap servos and cannibalizing the motors, but the motor shape/shafts/gears were different enough to make that a challenge. At least on the one Lexus unit that I bought.

One of the key problems lies with the servo arms. They are glued on or heat-welded. If you buy a replacement servo that doesn't come with the arm, then you'll have to surgically remove the old arm from the dead part. It's a major pain. The guy I bought from on eBay ships his with the proper arms attached.

Unfortunately, this was an expensive search. I don't get many chances to offer help back to this forum and wanted to share all that I'd found. Hope it helps!
 

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Your comment about 3 vs 5 pins is throwing me. I can go back and verify, but this is what I remember:

Gen-II vans: All front servos were 5 pin units regardless of model. 2 pins for the motor itself, 3 pins for the analog potentiometer that was used for tracking position.

Gen-III vans: All front servos are 3 pin, and the units are 'chipped'. CAN Bus system with digital instructions for identity and position.

You are saying there is a mix?
 

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Your comment about 3 vs 5 pins is throwing me. I can go back and verify, but this is what I remember:

Gen-II vans: All front servos were 5 pin units regardless of model. 2 pins for the motor itself, 3 pins for the analog potentiometer that was used for tracking position.

Gen-III vans: All front servos are 3 pin, and the units are 'chipped'. CAN Bus system with digital instructions for identity and position.

You are saying there is a mix?
I may be confusing Gen2 with Gen3 - this was a result of visiting various car parts stores. When we tried to lookup the servo that I needed, the guy said they only had the low-price 3-pin units which wouldn't work in the non-XL(E) models because the 3-pin variants weren't "automatic". I have a Gen2 XLE. I took this to mean that only the XLE and XL used the 5-pin servo's and all models below that used the 3-pin servo's.
 
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