Blower won't go to defrost

Thanks for the details! Will search on ebay.
Another question: did you try to deconstruct the original part? I just wonder: what does become bad inside - metal parts, or plastic, or dried lube?

 

Yes I took the old one apart. None of the tracks were worn through like the photos from Clas above. I am guessing just some dirty contacts. There are some pics and advice on cleaning in some of the other threads on this...mostly from the lower actuator. I assume if I clean it up and re-lube, it would would work. Be careful the plastic tabs that hold the case closed are very brittle.

 

Yeah, that kind of drive isn't going to move easily from external force. I dug out my mechanic's stethoscope and listened to the mix servo when it moved. There was a slight but clearly audible whir. But when it was touching the outlet servo and my assistant shifted the controls between "defrost/foot" and "dash vent" back and forth there was no sound whatsoever. A finger on the big white plastic wheel it drives didn't detect any motion whatsoever. Do servos fail like that? Seems more likely they didn't plug it back in or smashed the wiring when they reassembled the dash. If the door was jammed I would have expected enough slack in the linkage that it would have at least clicked when the state changed. The lower (mix) servo's plug is right there and can be reached without even taking anything apart, but I have yet to spot the upper (outlet) servo's plug. Does it face up or back? If the whole dashboard is disassembled can it be accessed from above?

The diagnostics are both B1442 (inlet) and B1443 (outlet). The inlet works but it makes a soft groaning noise when it shifts position. The diagnostics don't have a microphone, and the rate at which it moves seems reasonable, so I wonder what that inlet code is all about.

Also, has anybody ever seen an A/C amplifier that has actually failed? I have run into multiple threads where people had a diagnostic which said it might be the amplifier, and they swapped it, and it made no difference.

 

Have you got the manual? It looks like B1442 is "I sent power to the servo to move, but the signal back from the position sensor doesn't convince me it did." That's a possible scenario, even if you see the thing physically moving. Would indicate an issue with the sensor potentiometer traces, or the wiring. Should be feasible to check if you've got the dash out anyway.

I have had those kinds of potentiometer traces get very electrically nonconductive without any visible sign. I just rub them down with a Q tip and some contact cleaner (GC Jiffy Bath is the stuff I happen to have, which includes a light lube that gets left behind, but the brand probably isn't too important). They'll look just the same after cleaning ... but work.

The first car thing I remember having to do that do was the intermittent-wiper delay setting in my old Ford. It was a little twisty knob on the end of the wiper control stalk, and it wasn't really built to be removed. The wiper delay had just been getting longer ... and lonnnnger ... and lonnnnnnger, until they finally didn't intermittent-wipe at all, and when I managed to get the knob off, again there was nothing visibly bad about the traces, but a quick cleanup with the Jiffy Bath and it was perfect again. It was always kind of easy to pull the knob off after that, but I didn't mind because that meant if they ever got slow again, it would be easy to re-clean.

I've never seen them at the worn-right-through stage like the photos upthread, but it's perfectly clear how they could get that way, with a bad position signal making the ECU incessantly hunt back and forth slightly.

I don't think I've ever heard of an A/C "amplifier" ECU really being wonky, and I'd be surprised if I did. I think some people have a gut reaction, whenever something funny is happening and a computer's involved anywhere in that system, to jump right to the computer being the problem, that is, the one thing that's all-solid-state, no moving parts, protected in a box. The problem is almost invariably going to be somewhere else.

Unless ... a flood car. That A/C ECU is down pretty close to the floor.

 

The plug for the upper servo faces diagonally up and towards the front of the car. See drawing on page AC-151 of the service manual. There is no way to get to it from underneath the dash (without first removing the screws). Presumably, if you remove the full dash top you can get to it from above.

 

I don't think the car was ever flooded. At least, no signs of strange rust or mold and electronics have been reliable.

The plug position sbg_pa states is crazy in terms of easy maintenance, but it makes sense in that the upper servo seems to be rotated about 180 degrees from the lower one.

Is there any slack in the upper servo's linkage? The shaft that sticks out of the wheel has little protrusions which look like they need to be pushed in to let the connecting linkage come off. But the rest of that linkage doesn't look like it was designed to pivot away from its plane of rotation. Instead it looks like the linkage is supposed to be pushed on while the servo is moved into place (and reverse when coming off.) Anyway, if the linkage could be released then if the plastic wheel turns by hand it will rule out a jammed door.

This makes me remember fondly the mechanical cable connections on our old Protege 5's climate control. Yes, they would sometimes pop out of their clips, but the moving parts of the inlet and outlet selectors were within reach without taking anything apart.

 

Yes, the two servos are mounted with opposite sides facing the vent housing.

There is enough flexibility in the linkage that you could remove them in place *IF* you could get access to depress the locking tabs.

 

Just realized I mis-labeled the servos in one of the photos above. Sorry about that.
Here are corrected versions...

 

They wouldn't; the callout in the parts diagram is just a label, and is linked to a part number below in the page.

That's just identifying the kind of plastic, so recyclers know what to do with it. Polypropylene is the PP I think, probably with glass fiber, and I'm stumped on the M, but just because I'm not in the plastics biz.

 

Cool...I learn something new every day on PriusChat about all sorts of stuff!
Interestingly if you google "PP-GF20+M20" you get lots of hits from Toyota/Lexus actuators and a few hits from plastics manufacturers!

 

The "063800-0240" stamped on the part seems to be Denso's part number for the servo. To get the specific actuator arm along with that servo it looks like one must use the Toyota part numbers, but there is some confusion there. Here:


HEATING & AIR CONDITIONING - COOLER UNIT. 2007 Toyota Prius Hatchback HYBRID | Toyota


it says (summarized):

87106N Air Adjustment Control Motor 8710647120
87106J Air inlet door actuator 8710647090
87106H Blend door actuator 8710647100

Unfortunately in the diagram 87106N is clearly the "Air inlet" (since it is on the blower side) and 87106J is the "Air Adjustment control" (since it above the blend servo).

There do not appear to be separate part numbers for the actuator arms. So far I have not been able to find an actual picture of any of the 87106* parts on a Toyota site. On ebay sales of the 87106* parts tend to show just the denso actuator without the arm.

 

I had the dealer fix mine, as it was still under warranty from when they replaced the evaporator. As expected, they found that they had not plugged the outlet servo back in. Not as expected, somehow or other this trip also fixed the TPMS warning light being on. See:

No air out of defrost vents at windshield | PriusChat

 

Could use some help. My prius is stuck on defrost, no matter what I do, air only is coming out by windshield. So I guess I am asking what actuator do I need.
Thanks

 

You are looking for the mode control actuator. aka the "air outlet damper servo motor". There are 2 actuators on the left side of the HVAC housing. This one is located higher up, above "air mix" or temperature blend actuator.



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I would be cautious about jumping directly from "stuck on defrost" to "what actuator do I need".

mr_guy_mann has correctly named what actuator that is, if the problem is the actuator.

But I would not skip over checking whether there is a wiring problem to the actuator, or a mechanical problem in the linkage that the actuator drives. There have been threads here with such problems.

Also, Gen 2 actuators often become dodgy in a way that is very easily fixed by cleaning, with no need to buy a new one. Even if the problem is the actuator, a bit of TLC may be all it needs. Here is a thread with more about that.

Edit: hmm, maybe I shouldn't say TLC anymore. Nowadays it looks like you can't even find the meaning I grew up with until the second page of google hits.

 

fiddlesticks
(assuming that folks know what that is)

Here you go being all logical again. I mean really, suggesting that people should perform testing before loading up the parts cannon? Don't you know we gots all theez fancy eeelectronical comp-u-ters in there that'll tell ya what parts to put in? (most online places got volume discounts and free shipping!)

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Thanks for the help, I'm gonna remove and clean the easy to get to one 1st. Hopefully that fixes it, if not is there any videos floating around how to remove the upper one?
Thanks Again

 

Well, the lower one is supposedly for temperature (hot-cold blend). The upper one is for outlet direction (mode). A couple folk claim to have taken the mode servo out without "too much" disassembly. Must have skinny arms or an extra joint or something.

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Is the skid ECU mostly what's in the way? Maybe move that first?

I've never tried to get to the mode servo in a Gen 2, so just wondering....

 

Wow, what a job. Getting dash off was easy part. Had to remove a bunch of other parts which I didn't expect. None the less, it fixed my issue. Thanks for all the help.