Hi All .. Had to re-register tonight as a new member !!!!
I'm sure someone can help on this site .. I have a 2008 LS600h RSR with Air Con front and back but .. if I put it to Auto on the highest temperature setting (HI) and drive on the motorway it heats the car up as it should .. however without touching any of the settings and slow down when i'm in traffic or even come to a stop with the engine running the Air Con starts to blow Cold Air ??

Has anyone come across this before ?? .. it may just be a Temperature Sensor on the blink or something more serious .. it happens whether it's in 2 zone or 4 zone mode

Any help would be appreciated

 

wrong section, this is the 1st gen LS (1990-2000) model subsection but I'll try to help.

it sounds like you have air in your cooling system which heats up the various heater cores in your newer car.
running the car at speed keeps the water pump moving so hot coolant gets to the heater cores.
slowing down stops that flow which explains your experience.

now since you have a hybrid, there should be a pump that keeps hot coolant in the heater cores flowing. perhaps that's bad too.
you will need to have your HVAC system diagnosed for a proper repair.

 

Thanks Timmy .. really appreciate the reply even tho' i'm in the wrong section .. last night was a bit of a mare .. had forgotten my password and no matter what i did I couldn't get back in so had to re-register all over again !

I'm in Manchester UK so I'll take your diagnosis with me to my Lexus garage and let them sort it .. thanks very much

Malcolm