Out side temp Sensor

I think this is just a case of Ferrari not updating things. If you look at the parts diagrams on Ricambi it is obvious that the diagram for the 355 is the same as that for the 348. But in reality the cars are different. I don't know about earlier 95s as my car is June 95 production.

 

Too back up John I did not see in person so until physical confirmation I agree. I spoke as if I was possitive and I am but the info I saw could have been wrong as it was a post online and the 355 was being discussed at the time.
That being said I should not have stated it as fact.
I believe it was an euro car on a euro site so maybe someone with a early 94 could confirm here.

 

If you look at the parts diagrams for the 348 (any year) and 355 (any year) you will see that the 348 and 355 mirrors are different and only the 355 LH mirror shows the outside air temp sensor and part number for such.

 

Okay, I have a 1995 Euro F355 GTS. Ever since I purchased it from Bring a Trailer (BaT), I have been trying to figure out my HVAC problem. Basically, the heater is always engaged and only blows out of the top vents.


I have done a lot of reading before making this post to avoid asking a question that has already been answered, but I have hit a wall at this point.


I’m going through the diagnostic process by checking all the sensors to confirm that the system isn’t in a mode where it thinks it’s cold outside and is automatically engaging the heater. This is based on what I’ve read here. However, I am having trouble locating the exterior temperature sensor. I understand it could either be under the mirror or on the side of the box in the frunk. I have neither—see photos.


At this point, my assumption is that the mirror was replaced when the car was repainted, and the wrong mirror was installed—one that does not have a sensor—leaving my car without an exterior temperature sensor. I don’t know if there’s a quick way for me to diagnose this. I’m not an electrical expert, but I’m great at replacing parts. I have seen the reference sheet in this thread about using an electrical tester to check the temperatures of all the sensors, but I haven’t done that yet because I’m still trying to locate the fourth one.


As far as checking other things, the HVAC panel seems to be working. If I remove the motor controlling the air vent position, it moves based on the controls. When I turn the temperature knob to cold, I hear the compressor engage, and when I press Off, I hear the compressor turn off.


What would be the quickest way to check if my sensor is in the mirror? And how can I confirm if I have the correct mirror based on the wiring harness connection?

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Looks like you have a hole for the sensor, but it’s missing.

I dont know how it is mounted. Is it a push fit from inside?

You would think that if it was pushed inside, it would still sense some kind of external temperature.

If you still have access to the forward luggage compartment components, the easiest way to check it electrically would be from the ECU connector. The sensor will present some kind of resistance if it is fitted, open circuit if not fitted.

On your ‘95 car, the ECU is on the right hand side of the fan/fresh air assembly, close to the cabin bulkhead.

 

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Remove the yellow plug (by first pulling on the black "saddle" clip). Then check the resistance between pin 4 and pin 10.

Unforunately, I'm not sure of the orientation/pin numbering of the ECU connector.

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Alternatively, you could do a resistance test at the main door connector. Pins 11 & 15

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If you do do a resistance check, could you note the ambient temperature. It would be nice to get a ballpark figure for these sensors.

 

Here are some instructions on how to remove the mirror to get access to the sensor..

https://www.ferrarichat.com/forum/posts/146146534/

Ferrari 348 reference (but the clips are in a different position)

https://www.ferrarichat.com/forum/threads/355-side-mirror-glass-replacement.557453/#post-145504156

 

Here's a better graphic for the door connector....

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Note the unusual numbering. The Spider wiring is included, so ignore the extra pins.

So measure across these sockets on the door:

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