New owner with ventilation problem

I am in the process of putting everything back together so that I can try the system with the actuator wound one way and then the other to see if it will auto-set to the default windscreen position, and I spotted a fuse on a relay missing;

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So what amperage fuse should be there and what does the relay operate? You don't suppose it's for the distribution actuator??

 

Well I did the test where I set the actuator to one direction and started up the system, and then set it to the other direction and started the system in order to see if the system reset the actuator to the default screen position, but I'm afraid it made no move whatsoever. Other than applying power to the black and red wires to rotate the motor (which it does) is there another test to see if the potentiometers and the unit as a whole is working. I did briefly get another puff of smoke out of it again. After everything I've gone through I still view the actuator as the prime suspect.

 

I also did this but no effect. When I had the fan on 0 and disconnected the control unit and started the ignition the fan was off, when I set the fan to 2 and disconnected the control unit and started the system the fan came on a 2nd speed, so it seems it remembers the last used setting rather than finding a 'medium' setting as suggested above.

 

Hi John. Where from and what is the part name and number.. and dare I ask the price?

 

The actuator was out of the car during the test, but I can confirm that the air direction flap rotates freely. I took it today to an auto electrician and he declared it dead, not only the potentiometers, but now even the motor simply connected to the red and black. I've tried all the suppliers for a new one (including allferrariparts) but it is no longer available. I have found one second hand at £222 so they've got me over a barrel it seems. I can understand normal manufacturers giving up on parts for models over 20 years, but it is very disappointing that Ferrari give up when so many of their cars will be kept on the road indefinitely!

When I do get a replacement, not having made a record of the position of the flap relative to the shaft of the actuator (dooh!), I see there is a mark on one edge of the socket of the flap which I would presume coincides with the mark on one side of the shaft. You would think though that as the shaft has one corner 'cut' that the socket would be the same so you can only put it back in the correct position, but the socket is a square hole allowing the actuator shaft to go in in any of 4 positions.

 

Hmm... Turns out to be not much of an auto electrician - I just applied 12v to the black and red and it is still working (the motor at least) contrary to what he said!

 

John, sorry to question this but are you sure I should be checking for resistance in ohms rather than voltage? I ask only because I saw another post (sorry I can't find it to say who wrote it, it might be from another thread) which said;

"How basically the air direction control works is that the microchip runs as an Op-amp voltage comparator - it monitors the voltage on the middle pin of the flap motor's potentiometer ("pot") and the voltage coming from the control panel's air direction switch. The range of these voltages is usually 0-5 V."

 

The actuator is out of the car. Between the green and yellow there is no ohm reading at all except when you first touch the terminals and there is a split second jump to 170ish ohm then nothing, and that's without power or with power in either direction to the full extent of rotation. Also there is no reading at all when connected to the purple and yellow. When connected to purple and green there is nothing until the pin get almost to the end of its clockwise rotation. Fully clockwise it reads 0.9ohm. As you begin rotation anti-clock the reading quickly leaps to about 190ohm within about 30deg of travel and then the reading is gone. This is the only reading I have got, but I have got it reliably every time of trying. (at least there has been no smoke now)

From everything that's been said it would seem that the potentiometer is faulty. Yes It is only Eurospares who have s/h units. Now that we know that my unit unit is knackered there would be nothing to loose in opening it up if only to get a photo of what there is in there. I don't suppose there is any chance of even a boffin doing anything for it.

One thing I did find curious is that while experimenting with turning the direction flap manually to see where the air came out when in different positions, is that it is far from clear cut or cleanly divided where the air is delivered it's all a bit muddled. The actuator only has 180deg of movement so all settings must be within half a rotation. With the mark on the socket pointing down (South) I got vents & screen (mostly). South-East gave vents, East gave feet & vents, North-East gave screen, and upwards or North seemed to give an equal amount of air to all 3 directions. I found that there was no position which gave screen and feet which is one of the options on the control. I must say, having found a setting that spreads the air evenly it is very tempting to set it there and leave it there forever, but I have been trying to solve this for three years now (good grief!).

 

You're quite right and I had forgotten that I had done that [22 Nov 2018 page 3]. (This thread is now so long it's hard to keep up with it all). This is very bad in so far as even though the actuator is now junk the fact that it was tested as working in November means (or at least strongly suggests) that a replacement will not make everything work. Looking at my actuator I think the welded four joints look factory and it has not been previously opened. I will open it up and look for obvious faults, but if nothing is revealed, now that I have found there is a setting of the air distribution flap the gives an even amount of air to all three directions I think it might be best to set it there and leave it there.

 

OK, I've got it open (now and it has definitely never been opened before). The wires all connect to the circuit board cleanly, solder joints are good, no dry joints. The cogs are perfect. The smoke comes from the brush of the motor. In operation lots of little sparks come off the brush, but the brush is of a good length and is not in need of replacing. The brushes could perhaps be cleaned, but it won't affect the pot at all. I have repeated the test as above (the most recent test) with the ohmeter on the circuit board and the results are the same.

When I said above that it is poor that Ferrari have allowed this part to be NLA, it can be said of any part, but all electric motors with brushes cannot last forever as brushes wear down, spindles foul from arcing, and cogs wear. The unit is plastic welded shut, even though they could have used screws, so is not designed to be serviced (unlike say an electric drill which will be screwed together and will often be supplied with spare brushes) so this really should be always available, but nothing will be done of course (rant over).

 

You can see the motor arcing here;