I have lexuses350 2008. I am experiencing some problems with my ac system. Ac works perfectly fine when I set the temperature at lowest. Then it blows nice cold air. But when I set temperature at 22 or 23 degree Celsius then it blows warm air and gradually hot air. The outside temperature is 41 degree C. Then if I set the temperature again at lowest, after a minute it blows cold air. Don't know what could be the problem. I have visited my local mechanic. He says heater core and valve needs to be changed. Any good suggestions on that??

 

It could be the A/C flow sensor losing magnetism. There is a $5 magnet hack trick that has worked for many. If it is not that It is probably some other temperature sensor. Not sure why he wants to replace the heater core and valve.

What codes did he find?

How many miles/KM are on it?

Here is a link to the magnet trick. It is in the RX forum, but the ES has the same engine and A/C, as does the Camry and other Toyota/Lexus vehicles.

The magnet trick primarily applies to the B1479 code

See post 143 which has a photo showing where to attach it. If it does not work at first, flip the magnet over. Polarity matters. https://www.clublexus.com/forums/rx-...lution-10.html

 

You mean post #148?

 

I wonder if the small magnets you find in hard drives will also work, they're a bit bigger but also pretty powerful.
You get 2 per hard drive and can use old/discarded HDDs, but it's probably better than buying in bulk.

 

The photo is in both posts. Originally in 143 then reposted in 148.
Any magnet that sticks and fits will work.