Test recirc actuator without disassembly?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by pasadena_commut, Feb 14, 2025.

  1. pasadena_commut

    pasadena_commut Senior Member

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    I noticed today that the cold air coming out of the end vents was at exactly the same temperature regardless of the setting for fresh air/recirculate. We just went through that exact same problem on our Accord, where it would change state on the climate controller but the actuator wasn't moving. (It had probably been broken for a long time.) Is there some definitive test to run on this Prius that will verify that the recirc actuator is working? Other than taking apart the dash to see it in action. On the Accord if the car was stopped and it was dead quiet I could (just) hear the mechanism moving, but that didn't work for me on the Prius. My hearing sucks these days though, so if the Prius mechanism is quiet, my not hearing it isn't strong proof that it is broken.
     
  2. ChapmanF

    ChapmanF Senior Member

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    Drop the glove box and take the cabin filter out, and you can watch through the filter slot and see that door move.
     
  3. pasadena_commut

    pasadena_commut Senior Member

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    Thanks, will try that. Hopefully it moves.

    Looks like the air inlet servo is mounted above and to the left of the cabin filter, facing it from the passenger seat. The manual only describes removing it in the context of disassembling the blower. In the event that this one has failed, is it possible to swap one without tearing the entire dash apart?

    By coincidence the equivalent actuator failed in our Accord recently. Some disassembly was required, only around the glove box, and a lot of cable unplugging. Honda mounted the actuator on a metal plate which was fastened in with two screws on the side facing the cabin. So once all the cables which were in the way were moved aside that actuator on its metal plate came out easily. The Prius one looks tough, because the screws are aligned parallel to the long axis of the dash, and I'm betting that there is something in the way that prevents them from being removed in place, even if the top is off the dash.

    In terms of reliability and serviceability the use of actuators instead of manual controls with cables was a big step backwards. The biggest problem I ever had with the older technology was one of the cable holder clips slipping off its mount point, and then the cable would get into an odd geometry and it wouldn't work. Which was always obvious because when the knob turned it felt wrong, and sometimes one could hear the cable hitting things when it twisted around. Never took more than a couple of minutes to put the clip back on, albeit with some awkward body positions to reach it, then back in business, and it only ever did that on a single car of the many we owned. Wait, I once routed one of the cables wrong, after pulling out the climate control, but again, an easy fix. These actuators though, what a PITA. Usually. Not the ones which are mounted in an accessible location, but that is more the exception than the rule these days. Also, the list price for the OEM ones is, well, obscene.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    Yes I just did this yesterday and the generation too I'm not sure why I'm looking at the recirc actually I need the blend door which blends the heater core and whatever airs going to go over it which is on the other side of the car which is a lot harder to see but I've seen a video of how it works and usually the plastic is hanging up It looks like it's not lubricated or something but I think that may be the foot face and all those vents and the other one moves the damper up and down from hot to cold they're on the driver side next to your right knee and I've seen a few videos of the one that works the face feet defrost and what have you It can stick I'm not sure what's happening with my blend for my heat if anything I don't think anything. But just pulling the shock off your glove box and squeezing the glove box You don't even have to undo the filter door You can just hit the research or the fresh and recert buttons and see the door with the foam on it fold in and that's pulling air from inside the car across the heat or the air conditioning and back into the car and then when you hit the fresh portion the little door with the foam on it swings forward and pulls air from where the mice come from under the wiper tray I didn't know that one was likely to fail I thought the ones that failed were all on the driver side of the car interesting.
     
  5. pasadena_commut

    pasadena_commut Senior Member

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    Tombuk2 is correct, the foam door is right behind the glove box. The actuator on ours is working since that door opens and closes normally. It is also very quiet, it doesn't make the final "thump" some of these do when they close fully. It looks like the blower assembly needs to come out to access that actuator, and that means the top of the dash must come off, along with lots of stuff on the passenger's side. I'm hoping this actuator lasts a long, long time, because that would be a colossal pain in the butt.

    So, that takes us back to the initial observation - the temperature of the air coming out of the end vents, or at least the driver's side end vent, didn't change in fresh vs. recirculate in a setting where the center vents were heated. Why? Last time I checked the outside driver's side vent did blow cold air when the A/C was engaged on a hot day.

    For the current observation it was around 57F outside and 70F inside (as shown on the MFD in climate mode), and the end vent temperature felt much closer to 57 than 70. I didn't have a thermometer handy at the time. AC was not on, in any mode (defrost, explicit AC) and it wasn't in Auto mode. The outlet direction buttons work and redirect air up and down as indicated. The heater control works, but apparently not for at least that one vent, which didn't feel heated at all. I could stop the cold air there by closing the vent, I guess, but, well, strange system.
     
  6. Tombukt2

    Tombukt2 Senior Member

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    Yes I'm having the same problem right now in the '09 Gold work vehicle I can get the center vent on the right side of the MFD is the hottest next is to the left of the MFD and then coolest is the one on the far left at the driver window and I didn't think anything made any kind of shift in that unless you moved the position buttons of where the air is going to come out feet and defrost face only that sort of thing. Everybody keeps saying that they think it's the damper door that goes from cold to hot or whatever goes on I've got to go out and look on my parts car on the left side of the HVAC box and try to figure out which one of the dampers moves between the heater core and the evaporator core I think it's the furthest one back or the highest one off the floor or whatever The other one operates the position that you want it to come out of the vents and what have you according to a video that I've watched that seems to be the one that can get stuck and messed up the most is the one that goes from the floor to the defrost to the face and what have you looks like you need to keep that greased up lubed up or something because that's the one that sticks not the motor the mechanical levers the white plastic I'm just curious if the other damper plastics are the same they are the same but I don't know if they move as much as the plastics that move through the different vent positions there's a bunch of those and then the last one or two positions they're very difficult and very long throws.
     
  7. pasadena_commut

    pasadena_commut Senior Member

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    Run the diagnostics?

    Hold Auto and R/F switches on steering while turning the car on, then there is a flow chart for the rest in the manual at AC-37. Hopefully if something is sticking it will show up in the actuator checks.