355 Climate Control Vent Position...stuck at Defrost

I've got the same problem. I replaced the ECU and the stepper motor and neither helped. I finally removed the stepper motor, inserted a screwdiver to turn the assembly shaft until it opened up the center dash vents. Now I have air coming out the dash vents only and not just the defroster.

 

This is the small motor that controls the air deflection:

http://www.ricambiamerica.com/product_info.php?products_id=254040

It is located on the passenger side (exterior) of the evaporator box. It might be your problem.

 

No manually turned it to have air coming out of center vent only.

 

I've already replaced that motor and did not make a difference. Bench tested the old and new motor and both worked. This happened to me several years ago and I replaced the ECU and that took care of the problem. It has now happened again and I got a new ECU again and did not solve the problem. I'm stumped. I don't really want to keep replacing parts by trial and error.

 

John - Good luck on this one. It's happened to me twice; ie, got stuck in the"defrost" position. In the shop (a different one each time) the technician/mechanic fidgeted with it a bit, and each time it mysteriously started working again. Now, I just leave it in the "face" position all the time, although that may only be practicable here in Sunny California.

Doug

 

Could it be the HVAC panel? If so, let me know and I can send you out an extra I have to test and rule that out. I have about 12 of them here....

 

I'm thinking it is the control panel. I already spent $1600 for a new ECU and that wasn't the problem. It would be great if I could try out a new control panel. Let me know if that's possible.

 

As told me by Pocono Sportscars, kill the power, turn back on, key to position one, turn on HVAC. It does a relearn, presto, everything works.......

 

I've tried the turning off the battery and then turning the key on to reset the computer last fall and that did not work. I had this happen three years ago and replaced the computer and it was fine for three years. This time, even replacing the computer again does not seem to work.

 

Robbie at Stickynomore was nice enough to let me try a different HVAC panel to see if I could get my A/C to blow out of vents other than the defrost but that did not work.
The motor that opens the vents will turn but then goes right back to defrost setting. So it has a new ECU, the motor works, and HVAC panel is ok. What to look for next?

 

Did you get stuck on defrost right after the install of the stereo or did it happen sometime after?

 

Opening an old post. My ventilation selector knob doesn't seem to be working. Air is coming out of all vents no matter what direction I select. Blower works fine. Is this most likely the timing actuator motor?

 

same here mine does not work either regardless of switch position...it only comes out of the defroster! Anyone else have any info on this? would love to get this fixed

 

As you can see, no one responded to my post so I sold the car. LOL! Unfortunately I can't help you with this other than thinking it is the actuator motor that controls the air deflection. Should be an easy fix and the part is available through Ricambi. Good luck!

 

If the air is stuck on defrost vents only, it is likely the actuator which rotates the tambour door: Ferrari Parts : 63307100 TIMING ACTUATOR : Ricambi America

Could it also be an A/C ECU? Yes, but it seems far less likely. Put your hand on that little actuator motor and try changing air directions on the panel. If you don't feel the little thing vibrate, then its likely dead.

 

Thank you for the replies! I guess my next step is figuring out where the sucker is located and how I access it. Any feedback on this? I'm hoping I won't have to tear the whole dash apart?

 

I have a car in the shop now with this very problem.
95 355 spider came it with the A/C only blowing through the defrost vents.

I only had about an hour or so to look at it, but here is what I found.
1. The selector actuator motor operates by applying 12v to the motor but I can't verify the feedback potentiometer because I don't know the range. I ordered a new one, at this point probably just for reference.

2. The ECU reports to the SD1 that it doesn't know the "treated air temperature". The ECU also reports no errors! I pulled the sensor but it looks OK. Fiddled a bit and got the ECU to occasionally read the treated air temperature but it always reports -20C. Probably not correct. Even so, at this point the ECU will work the actuator. At 80F the sensor is around 7k ohms. The air doesn't come out very cold even though the compressor turns on and off. ECU might be adding hot water.

3. I opened the ECU can and found evidence of some minor water intrusion. Cleaned it and touched up some oxidized points.

I'll be getting into it on Monday. I'll post what I find.

 

Awesome. You'll be helping a lot of people by posting results. Thanks again.

 

Try this, it might help https://www.youtube.com/watch?v=IKjQGPnehjI

 

This is what I found.

The ECU has 8 dip switches in it; I guess for configurations.
I sprayed contact cleaner into the switches, not sure if it got in because they may be the water tight type. I then moved each switch back and forth around twenty times to clean their contacts.

Bingo, the system started reporting the correct "treated air temp" and the flap directed the air by my mighty command. Sorry.

The climate ECU drives the hot water valve directly. I've seen cars where this output fails so the A/C is only half cold. Since we mostly drive these in summer, I recommend turning the hot water valve completely closed and then unplugging it.

Hope this helps.