I noticed one day that my a/c was not really cooling the interior as it usually does. I have the Dual Climate control OFF. Temp set to low. The driver side and drivers center vent shooting out cold air.. The Passenger side and center vent is shooting out warm/hot air. I did some research and on the LS / GS Forums and a few people had a problem with the servo motors. I took my glove box apart and increase/ decreased the temp and I do see the motors moving the doors. I know there are servo motors on the driver side, I have not checked them because I think they control the driver side. Though I could be wrong.
Lexus use's MPa to check the pressure.. when did the conversion, the low side should be between 21-36psi and the high side 198 - 227psi.. Everything falls into that range.
Any suggestions????

 

I have the exact same problem, but I haven't had a chance to rip apart the dash.

Low on coolant? Thats the next easiest.

 

I had this problem maybe 8 months ago. Can you turn on dual mode and set the passenger side temp a lot lower to see if it's blowing cold air? When I did that to my car, it works. I check the error codes and found a log about servo motor offset (can't remember exactly, need to search my posts). I was going to have the dealer check it since I have extended warranty, but it started working fine again.

I think I was messing with the temp settings because the car was working, just seems that the temp setting reading was off.

 

^Try that, and if that fails reset the entire vehicle's systems by disconnecting the battery for 20 minutes. It'll force the car to re-learn everything and hopefully tell the HVAC system to start with at a default factory setting.

GL!

 

VTsuckah: yea the first thing I checked my coolant and it's full. The last time I've added coolant was last year when I did a drain and fill. Thank you..

nosurprise: yes I have tried that dual on and off also setting the driver side higher temp and the passenger side lower and vise versa. Still no luck.. Thanks for your input.
The part that sucks is that my extended warranty expired this Feb 2014

Gville350: I just tried what you told me. Also turned on the headlights, left the doors open ( which triggers the dome lights) with the batter UNplugged to make sure the power is completely drained.. Still no luck, maybe I need to drive it awhile to relearn?? If this not fix itself or if anyone has more suggestions by tomorrow afternoon, I'm just going to take it into a shop...

I really appreciate everyone's input!! Thank you!!!

 

Have you checked your refrigerant? When it is low you will get cold air on one side and warmer to hot air from the other side. Happened on my Sienna, Scion xA and my Saab 9-3. Quick recharge fixed it right up.

 

The A/C system should work as you tell it to, no matter. From what you described, it sounds like a visit to a shop is in your future.

GL!

 

Yes I did check the freon. That's where in my subject I described the MPa to psi levels and everything falls into the range Lexus says it should....

 

Yes! I dropped it off at a shop a few hours ago. I'll reply later with an update just incase anyone has the same problem in the future...

 

So I got my car back today. The mechanic he checked the pressure on the A/C and it meets specs. The problem was one of the doors in the a/c unit needed to be recalibrated / adjusted on the passengers side.
It was a $35 fix. I tried to get more info out of him but was to busy with other customers picking up their cars.

 

^Well, at least it was a cheap fix!

 

Nice! Cheap fixes are always the best.