This is on weird AC issue on my is350

With AC ON:
it blows cold air when the car is moving. When I came to a stop and waited for green light, the air blow warmer and warmer and smell bad until I move the car again.

Needs a recharge or something went wrong with the AC?

Check to see if your coolant temp goes up at stops, when the car is low on coolant(possible leak) the car will get hot at a stop and shut off ac to keep from overheating. Otherwise the refrigerant might have a leak and be low enough to stop cooling at times.

I have the SAME problem EXCEPT it occurs at random times. It is not limited to stops at red lights. For me, the AC is on LO and recirc. Every now and then, the air would get more humid and it's obvious the AC is not on even though the button says it is.

Btw, I also have a 350 (2010). Not sure if this is isolated. I would be interested to hear.

same problem here and have a 07 is250. sometime when driving on the freeway i have to push on the gas so it can down shift to 4th gear so it can turn on the a/c again. ill check all my fluids but not sure if that it, the a/c blows super cold when working so dont think it leaking or low on freon.

if someone finds a solution please post, sucks when you have other people in your car and they keep reminding you how the a/c sucks lol

intresting.....

Hmm this sounds like low refrigerant in the system. When you make the car downshift you cause the revs to rise making the compressor work faster which in turn would raise the pressure activating the high pressure switch.

I'll let you guys know what could be the issue in a few days. My car is at the dealer for diagnostic.

^ nice keep us updated

it's the radiator fan & relay. The one on the right. They suggested that I replace the fan + relay + thermostat all together. Their price = 1k + tax. Sewell has the fan for $45 and the thermostat for $39, still trying to find the delay. I'll spend under $100 and do it myself :-)

^ lets us know if that fixes the problem... if so ill do the same

Ah shet. Another issue with this car... Subscribed 4 when my car decides 2 do the same thing

did you ever get the problem fixed??

check the coolant. the is from 08-10 has contaminated coolant issues that clogg up. check if the tempertures change correctly driver and passenger. check tsb L-SB-0018-11 heater core restriction.
Some 2008 – 2010 model year IS 250/250C and IS 350/350C vehicles may exhibit a variation
greater than 20F (11C) in HVAC vent temperatures between the driver and passenger side when
heat is utilized at the same temperature setpoint. Use the following repair procedure to address this
condition.

Do you have a PDF of that TSB? I can only find one online, but its referring to the Window defroster...

Do you have PDF or any kind of document we can referece?
Thanks