Confusing Heating Question Is250 Se-L

finest1 · April 9, 2011

hi all,

i wonder if someone could help. i do not understand my heating system.

if i'm driving during the day and i put the heating on to 21.5 degrees, i get warm air through the vents. this is a good thing. when heating has been off for a while, and you put the heating back on to 21.5 it blows cool tepid air, not freezing air. so i touch it up to 22 degrees. same thing cool tepid air. for example. today i drove to hastings from london. in the morning after the car has been running for 20 mins, i put heating on at 21.5 as mentioned above. i turned it off once sun was shining through car and we felt comfortable. all ok. now 8 hours later after our day out, we are driving back to london. we feel chilly and put the heating on 21.5 degrees. it blows out tepid cool air. i left this on for over 20 mins. so i touch it up to 22.0 same thing. i again touch it up to 22.5 no joy. when i put it up to 24-25.0 warm hot air blows through. my question is: is this normal? in my old gs300 i can leave it on 20.0 degrees, and its warm air. its only on mega cold days it goes up. so it seems that during the day its ok, and in the evening its not, or is this coincidence? i'd like to hear from other drivers if this happens to them. what is the temp borderline where warm air kicks in? by the way, i don't use climate control, im manually adjusting the climate for example:

press climate

choose fan speed

turn off "a/c" (bottom left)

and adjust temp myself

many thanks

finest1

Shepherd · April 10, 2011

In my limited understanding of this, I think the way it works is that there is an internal temperature sensor . If the internal temp is more than what you have set on heating then cool air would blow (air con if switched on) otehrwise,warm air will blow. Now the internal temperature can vary a lot independant of how it feels. It may feel quite cool to you but there may be a different temperature pocket sat around the temperature sensor.

Again that is how i think it works, I dont really know this for a fact

hi all,

i wonder if someone could help. i do not understand my heating system.

if i'm driving during the day and i put the heating on to 21.5 degrees, i get warm air through the vents. this is a good thing. when heating has been off for a while, and you put the heating back on to 21.5 it blows cool tepid air, not freezing air. so i touch it up to 22 degrees. same thing cool tepid air. for example. today i drove to hastings from london. in the morning after the car has been running for 20 mins, i put heating on at 21.5 as mentioned above. i turned it off once sun was shining through car and we felt comfortable. all ok. now 8 hours later after our day out, we are driving back to london. we feel chilly and put the heating on 21.5 degrees. it blows out tepid cool air. i left this on for over 20 mins. so i touch it up to 22.0 same thing. i again touch it up to 22.5 no joy. when i put it up to 24-25.0 warm hot air blows through. my question is: is this normal? in my old gs300 i can leave it on 20.0 degrees, and its warm air. its only on mega cold days it goes up. so it seems that during the day its ok, and in the evening its not, or is this coincidence? i'd like to hear from other drivers if this happens to them. what is the temp borderline where warm air kicks in? by the way, i don't use climate control, im manually adjusting the climate for example:

press climate

choose fan speed

turn off "a/c" (bottom left)

and adjust temp myself

many thanks

finest1

LexusForever · April 10, 2011

hi

the system reads the actual temperature in the cabin and then blows either hot or cold till it matches the temp you selected. it's not like normal systems with a dial that you manually turn which physically closes or opens flaps in the pipes. to be honest, i never turn auto off on mine, and it stays on 22 permanently throughout the year and generally never needs changing.

have you tried leaving it on auto and seeing if that helps? when on auto, it usually blows the air out of the vents which need it most and controls the fan speed, thus avoiding blowing cool air in your face. this is my 4th car with climate control and they have all behaved in the same way.

hope that helps :)

regards