I've searched pretty extensively and found several posts that are ALMOST the same as my problem -- but not quite...
My '96 LS400 runs very well and is well maintained. But I've noticed that when I go on a long trip (two hours or more -- it usually takes quite a bit more than that), my heat or A/C airflow fades and eventually quits blowing. It's not a coolant level issue -- it does the same with A/C as with heat. Different RPMs don't make a difference either. In order to get the control back, the car has to sit for a period of time (sometimes stopping for lunch will make it 'all better', and sometimes it requires an over-night stop.
Just driving around my normal daily life, it never happens -- so of course, I can never get it to my mechanic while it's acting up because I have to be several hours from home before the problem ever shows up!
It would be my guess that the problem is located in a control that directs an airflow 'door' somewhere. When the problem occurs, you can hear the fan running as normal (responding aurally to manual adjustments in fan-speed). But the air quits flowing from ANY of the vents. The air always comes from the correct ports (defrost, face, feet) when it IS flowing. But when the problem surfaces, the air-flow simply tapers off to nothing.
It's really maddening since this car is my preferred driver, and it's BEAUTIFUL for long trips -- except for this! If it's during the need for A/C, it's merely an inconvenience, as I don't mind driving with my windows down for a while. But when it's cold out (like on our trip home from our daughter's place more than three hours away last night), it can become a hazard, since I have no way to provide ANY airflow to the windshield, and keeping the windows from fogging up can become very challenging. (Especially with two adults and two dogs, like I had last night...)
Anyone else every experience this? With winter here, I really need to find a way to address this. But since I can never experience the problem except when I'm a few hundred miles from home, it's never practical to get it to my mechanic to examine things while it's acting up!
Thanks in advance for any advice or shared experience...
Recently, my battery died on my 2010 ES350. After jumping it, I noticed there's heat coming out of the driver's side (and rear) vents, but cold air coming out of the passenger's side vents. I checked fuses and everything seems to be fine. After some research, read that maybe the AC Blend Servo Door is stuck (or maybe I shorted it or something when I jumped it). Does anyone have any other thoughts/suggestions? Am I on the right track? If so, can anyone point me to a step-by-step of how to get to the blend door servo (I don't have a repair manual) to check or replace it?