Been getting some odd behavior from my A/C system lately, usually at night for some reason. I live in Vegas and what happens is that the A/C has been working merrily away but will decide to drastically reduce the flow from the dash vents, even though it is plenty hot enough to need them running. If I manually select the vents from the touchscreen full flow of cold air is restored right away. I don't recall this happening during the day when the sun is shining. I wonder if one of the dash vents is leaking cold air on to that damned aspirator gadget.

My understanding of the climate control system is that it regulates temperature by changing the fan speed and the amount of cooling via the variable displacement compressor. Will the temperature sensor also call for the flow to be reduced by shutting vents? If so, the calibration of the sensor must be way off and it must be VERY slow to react. At night it can still be 100°F (38°C) at midnight in this city, so when those vents close up the car gets hot and stuffy inside very quickly.

Just to add to my cup of joy, the A/C has started the "stinky socks" smell from time to time, so maybe my A/C drain is obstructed too.

 

Maybe the in-car temperature sensor is faulty. You need someone to read the OBDII codes - B1A61 is the code for a temp sensor fault. You can get the full 8-character code with the Jag diagnostic system, but either subcode means a dead sensor.

 

I have not experienced same issue in my Jaguar but in a previously owned Lexus the a/c system would "cycle" at points in time (when in very hot and humid weather) between dash vents and defrost mode. I believe this was intentional to eliminate any condensation that may form on interior glass due to humidity.

 

I to am having a simular problem with my AC.
Been working fine ,then it suddenly starterd , placed the AC on auto, set the temp at 65 cold air coming from the vents on drivers side & a little warmer on the passenger side ,????? Not hot but warmer. Maybe we have the same problem . Bernie

 

Well, I haven't seen the problem here in the last few days. Maybe the temps are too high. Wait and see, I guess.

Maybe I cleared something when I did the "manual mode, select dash vents, full fan, recirc, close the dash vents" trick to pressurize the air handler to open the duck bill. There was no visible water afterwards but the smell seems to have gone for now. Who knows, it has been so darned hot here lately even a good dump of water may not show under the car as it would evaporate too quickly. It's been 100°F at MIDNIGHT at least twice in the last week. Was 107°F today with 19% humidity, quite a relief after yesterday's 112°F.

 

Just a quick update.

The A/C has been cooling me just fine these last few days when out during the day. However, it did do the semi shutdown one night, but I THINK I know what is going on.

The A/C sensor measures air temperature, but we humans sense the air AND any radiated heat from other places, like the heatsoaked car body and windows. So, the sensor says "Yep, required temp achieved", cuts the flow and now my skin is left open to receive all that radiated heat directly. It is a weird sensation and makes you think that the vents have started blowing hot, but they haven't.

Anyway, that's my theory and I'm sticking to it....at least until the dealer checks the codes.

 

Interesting theory but I can't buy it considering there are only a few complaints of this problem. What seems to be interesting is that the problem is on the passenger side only. What side does this problem happen with RHD cars , is it the driver side. Sounds like a "blend" type of module. Lets see what the dealer says.

 

I am having a strange problem with air con fan noise, I thought it was a leaf
but on further investigating I found that changing the speed of the fan doesnt change the noise, also the fan momentarily cuts out for a second when turning right (RHD car) I now think its the fan under the steering column to draw air over a sensor for temp contro, l wonder if theres a fuse for this fan so I can see if noise stops
anyone else have this problem?

 

Razor, you're on the X150 (XK/R new shape 2006+) part of the forum - you need to pose this question on the X100 (XK8/R 1996-2005) sub-forum.