New owner with ventilation problem

Yeah, I don’t know. I’ve already ordered a new gear for it and hope that’s all the system needs. It is still an unknown as to whether the rest of the system works correctly, but I am hopeful. Oh well. When I bought the car, I decided maintenance would not be deferred. When I find problems, they get fixed, even if it’s “unnecessary” or overpriced. I don’t want little issues piling up.

As for the gear, I’m a little surprised it is THIS destroyed. I figured a small section may have broken off, but this thing totally disintegrated.

Does anybody have more guidance on removing and reattaching the necessary components to remove and replace the gear? Is the gear itself press-fit onto a shaft? I’d like to have a solid game plan going into it instead of guessing and removing parts unnecessarily. Thanks!

 

Wow, case opened perfectly. Brilliant. Good for you!

It's great case edges remain intact and you could put them back with no opening traces.

Sorry the totally cracked gear is horrible to look at. Yes, a aging gear cracked only a matter of time no matter it is used or NOS which you just proved. And, sometimes the gear is only partially cracked but square shaft still can move.

You will receive a two-piece new gear identical to the genuine/original gear which makes your NOS alive. Beside solid which is the basic, it is smooth and quiet.

 

Yes, not worthy letting little issue ruins the vintage of a Ferrari. That is exactly the reason I make the two-piece gear identical to genuine/original.

To take out the gear, there is no special mechanism/component to be careful and, while there are two layers plastic rivets inside, only several of the lower layer rivets close to the gear need to be separated.

Although the plastic rivets inside look a bit different from the 4 corner rivets, they are still plastic rivets but grid pressed and thinner. The same, use knife to cut the grid portion and pry. Be careful not to lose the 3 tiny off-white washers on the iron center rod.

 

There are 6 plastic rivets on the lower layer/panel as the red circle on the picture.

I usually left 2 on the left side unseparated and pried right side and tilted up the panel so that gear could be taken out.

Start prying where the blue arrow indicated.

Hope it is specific enough.

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Incredibly helpful. Is the gear press-fit onto a shaft that it needs to be removed from or is it just set in place and is retained by the case?

 

For a gear, there are a iron center rod along with 3 tiny off-white washers as well as a two-piece gear. The two-piece gear consists of a disk shaft / worm gear and a rubber gear / crown gear with different materials. There must be a reason Ferrari doing so.

Assuming the "shaft" you mentioned is the "iron center rod" I am talking, the iron center rod is inserted into the hole of the two-piece gear. The end of rod is just hold and fixed by a hole on the lower panel meaning the rod could be removed together with the two-piece gear but I usually left the rod in place.

Assuming the "shaft" you mentioned is the "disk shaft" I am talking, the rubber gear is not simply pressed onto the disk shaft. Disk shaft and rubber gear are combined and fixed especially by the 8 holds and that is why over-molded meeting the requirement.

No worry since what you will receive is a combined two-piece complete gear. What left is only to put the gear hole on the iron center rod and slide the gear to the end, put 1 tiny off-white washer back and press rubber gear down to the original position. Done.

 

Correct a typo. "8 holes".

With the 8 holes passing through the disk, the over-molded gear could be firmly fixed on the disk shaft. Had to admit a unique and well design by factory but need more work than just one-piece.

 

I am currently waiting for my replacement gear to make its way through the mail system (it cleared customs, so it’s down to the USPS to get it the rest of the way to me) and figured I might as well tackle removing the broken gear.

As Vincent suggested, I began by shaving the tops of the plastic rivets on the right hand side of his picture and then pried from the blue arrow in his picture. It took a little gentle persuasion, but eventually popped up from the far right plastic rivet.

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After that, I started moving my way along toward the left on the edge closest to me as viewed in the above picture. I gently pried some more until the plastic piece popped free of the next plastic rivet.

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After that was the plastic rivet closest to where the broken gear meets the gear on the motor. A little more gentle prying and that popped loose. From that point, I was able to lift the plastic plate far enough to slide the broken gear off of its shaft and remove it.

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Don’t forget there is what appears to be a small bushing at the end of the broken gear, as you can see here:
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The gear slid off of the metal shaft very easily:
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Now I just wait for the new gear and reassemble everything. So far I’ve managed to avoid breaking any of the plastic rivets, so reassembly should be easy with a little cyanoacrylate to assist in keeping the case held together. I’ll update when I make some more progress. Hope this helps anybody needing to go through the same process.

 

Great job that you left the plastic pins/studs all intact. Brilliant update!

Can't image the gear in such a expensive NOS actuator is totally toast! "Aging" issue is only a matter of time.

Thank you very much for your patience, as USPS tracking record shows, the parcel arrived at USA on 3/17 seems like customs clearance took five days until 3/22. Very different from previous deliveries.

 

US Customs finally released the package to me and it arrived a couple of days ago while I was out of town. Got back in town today and managed to get the new gear installed and reassembled the actuator.

I reinstalled the actuator on the car and powered everything up and the tambour rotated through to the stops in each direction. I selected each option on the HVAC panel and the tambour moved to a new position with each selection.

The only problem I’m left with is that the air is not going exactly in the direction selected. When I select mixed between face and floor, it is fully directed to the dash/face vents. I made sure to line up the mark on the actuator male end with the mark on the tambour female end. What might be the reason for the inaccurate indexes? My understanding is the initial power-up cycle tests the limits of rotation and then the indexed positions are based off of that. This might be where the potentiometer readings will come into play, I suppose. Either way, I count this as a big win.

 

Is the relationship between the square drive and the potentiometer fixed? Or is it possible to detach the square drive from the potentiometer?

How sure are you that you aligned the marks? When you're working upside down, things can go awry.

 

I was wondering if the relationship is fixed. It may not be and it is possible it changed slightly during the gear swap, but the change would have been very minimal. I assumed the physical stops inside of the actuator set the limits (which are the memorized potentiometer readings in the HVAC ECU). Based on that assumption, I kind of figured that if the marks were lined up during installation, the physical limits would be correctly indexed to the desired ends of rotation of the tambour. Whatever the potentiometer readings were when the ends were reached would now be the reference limits in the HVAC ECU and all other positions would be based off of those limits. All of that may be incorrect, but that’s the way it would work in my small brain. Hopefully my explanation makes sense.

I suppose this all assumes that one half of the physical stops inside the actuator is directly attached to the output shaft/gear and that the mark on the end of that cannot change in relation to the physical stops on its gear.

I am 99% sure the marks are lined up. I was working through the passenger airbag hole in the dash when I installed it, so it was easy access and visibility.

 

It's possible that te potentiometer is 180 degrees out of phase with the "mark". I don't know if that would make a difference.

 

Potentiometers can have minor variations. I think the physical endstops of the actuator should lie between the limits of the potentiometer and the HVAC controller checks the resistance values at the limits. If the drive is detachable from the potentiometer, I can see how that could cause issues.

I think you would have to remove the actuator and see what it does during the power on test.

I have a video showing which in direction it should go in during the approx. 180 degree test if required. If the driveshaft is 180 degrees out of whack as John suggests, then maybe the HVAC is recording the other 180 degree range and the backsides of the endstops.

 

https://www.dropbox.com/t/qiP386drL33qgOlf

After reviewing the video, the direction of travel may depend on the starting point. It looks like my actuator travels clockwise (in the orientation shown in the video) and then anticloclockwise, but I'm thinking if the actuator was already at the far clockwise endstop, it may go anticlockwise first. Maybe a better test would be to set it up in the middle, then see in which direction it goes.

 

There are stops in the actuator that limits rotation to 180 degrees but the potentiometer could be installed in either position with the resistance at min or max. I don't know if it makes a difference because the direction vent is symmetric as I recall.

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There seems to be different endstops. See John's photo:

https://www.ferrarichat.com/forum/posts/149018550/


I suppose you could always do a resistance check on the bench.

Drive the actuator to the endstops with a 9 volt battery and record the resistances across the green and purple/black wires.

I get a few ohms (5) at the fully clockwise position and around 1.7k at the fully anticlockwise position

 

i.e. with the actuator sitting flat on the bench with the drive pointing upwards.

 

Here is a video of the initial power-up. The yellow airbag wire is toward the front of the car. This is a view from the top down into the center dash vent. The video is kind of long and lacks context because I didn’t know I’d need to start the car to make selections, but you can see direction of rotation during the initial power-up. It may be worth disconnecting the battery again and letting the HVAC ECU learn everything again before I dig in too far.

The later part of the video shows different selections being made and it seems like most settings are somewhere in the middle of where they should be. It’s hard to tell.

 

I’ll probably get to the bench test later this month. I’ve got a lot going on at the moment. Oh well, progress is being made

 

Yeah.. not really sure what I'm looking at here

To be continued...

 

I do know that my actuator started in almost exactly the same position as yours and rotated in the same direction as yours on power-up, for what that’s worth.

 

Have you simply mounted the actuator upside down (if that is possible). In which way does your wiring harness point? Forward or aft?

 

That’s entirely possible. The wiring harness is pointing forward.

I’m not sure if the connector would reach if I mounted it upside down, but I’ve done dumber things.

 

Disregard.. My harness is pointing forward, too.

I just checked, you can't mount the actuator upside down. The drive wouldn't go in the hole if you did that. The drive is offset from the centre of the actuator mounts.