01 Ls430 Heat Only Hot On Highest Setting

[DobieG]

Hi, all!

Haven't had to post too much since (thankfully) problems with my LS are few and far between!

I noticed this evening as I drove home that my normal "evening" setting of 75 degrees didn't seem as warm as usual. Bumped it up to 80 degrees and seemed the same. Didn't notice heat until it got to the HOT setting (86 degrees, I believe). At that point it was blazing hot! Let it run for a few seconds, took it down one degree and seemed to blow cooler again, with what seemed to be little or no heat, just cool. It's only happened this one time and I will see if it persists tomorrow. Outside temp was between 68-70 degrees.

Just thought I would put it out there to see if any others have/had this type of problem.

Thanks!

JIM

[wwest]

Hi, all!

Haven't had to post too much since (thankfully) problems with my LS are few and far between!

I noticed this evening as I drove home that my normal "evening" setting of 75 degrees didn't seem as warm as usual. Bumped it up to 80 degrees and seemed the same. Didn't notice heat until it got to the HOT setting (86 degrees, I believe). At that point it was blazing hot! Let it run for a few seconds, took it down one degree and seemed to blow cooler again, with what seemed to be little or no heat, just cool. It's only happened this one time and I will see if it persists tomorrow. Outside temp was between 68-70 degrees.

Just thought I would put it out there to see if any others have/had this type of problem.

Thanks!

JIM

I my experience you seem to be describing normal, perfectly normal LS HVAC operation.

The OAT, Outside Air Temperature, Sensor is in the HVAC control loop. With it already fairly warm outside the system isn't very likely to provide really warm (discomforting for many of us.) airflow. Except, as you noted, at EXTREME settings in relation to the (already warm, warmish) temperature of the incomng FRESH airflow.

And then if the sun was shining brightly (it does that in the evening a lot during our long summer days) the HVAC's solar radiation sensor will even be in the act to "tone down" the level of system "heating".