lexus600hl

I have "heard" about infra red heat sensors for rear seat passengers on the LS 600.
Can someone please elaborate? How does that work.
thanks

aypues

i believe it is only for vehicles equipped with the Executive Seating Package, which is also available on the 460L.

The infrared body temperature sensor (not to be confused with radiant heat sensor for the rear a/c) measures the body temp of rear passengers on the lap, body, and face i believe - it will then make any necessary adjustments to maintain the occupant at their desired temp setting.

lexus600hl

I believe you are incorrect. I think the infra red is a part of the package with auxilary rear cooling/heating system (which I think all 600HLs have and is optional in others). It is completely unrelated to executive seating package - because you can have rear cooling/heating system with and without executive package. The rear cooling system makes the usable trunk space smaller because it has auxillary blowers etc in that space.

What I don't understand is - I can set the temperature I desire, in the rear seat control. Lets say I set it for 72 degrees. What exactly does the infra red system do for me? I have already set the desired temperature.. Does infra red sensor change the fan speed? I can't figure it out.. Because even if there are no passengers on the rear seat, I suspect that the car will maintain the same 72 degrees in the rear also.

lexus600hl

What is a radiant heat sensor for rear a/c? I have not heard of this being in my car. What is it and what does it do?

CJITTY

the sensors are located on the headliner, they look like faint red LEDs sort of. If I am not mistaken, it helps the A/C system to faster regulate the temperature and keeps fluctuations to a minimum (as explained to me by others). And you do not need the executive seating package to have this, I have it in mine and I don't have exec seating

lexus600hl

I assume you are referring to Infra red sensors? Does it actually take a measurement of our body temperature? Meaning - if there is no one there, would the temperature variation be more than if there is a human?
Or is it that the infra red sensors simpy sense the "ambient" temperature in the rear seat area?
Just curious.. whether or not the body temperature is being monitored.. because.. of clothing.. I am guessing that the infra red would measure the ambient temperature - infra red being more "active" than a simple temperature sensor elsewhere

CJITTY

I would think it would always be working when the rear a/c is on. If there are two people back there, you are adding more heat to the interior just from their body heat, so I think it will constantly be working as people leave/enter the car, etc...just trust that it is working as intended

aypues

In all models with rear a/c (4 zone) there is a radiant heat sensor that measures the heat gain from solar rays and will make changes to cooling based on increased heat hitting the rear sensor. The front has its own radiant heat sensor at the top of the dash close to the windshield which will send data to the front AC.

For both the LS460L and the 600HL:
Only the Executive pkg has the infrared body temp sensor which measures the rear occupant's body temperature to make changes as well as the radiant heat sensor that all models with rear AC share. It is only referenced in the Exec pkg literature on Lexus' own website. The rear seat upgrade models do not have the infrared body temp sensor. See proof below:

See page 8
http://pressroom.toyota.com/article_...rticle_id=2576
See page 9
http://pressroom.lexus.com/article_d...rticle_id=2657

lexus600hl

very informative! I appreciate such authoritative answers. Thank you.