After 4 years and 75k miles the oem battery finally needed replacement. Pretty incredible since average battery life is no more than 3 years in the 20 years i've been in the desert. The battery was out of the car for about an hour, but as far as we can tell the only settings not retained were radio presets and climate control. My phone was still stored. the only issue we're experiencing is the climate control seems to not turn automatically on intermittently. Most of the time you go to the car and start it up, ac and fan kicks on and everything is on auto. Twice the car starts but the climate control is off...fan off, no ac. Anyone ever seen this before and remember the fix? Out of warranty of course so trying to avoid the dealer. Thanks for any info.

 

If 3 yrs is normal for desert, and 4 years is great, I'll be expecting 12 years out of mine. I've only ever replaced a battery once, that was in a 9 yr old Chevy. My Sienna just passed 10 yrs and nearing 100,000 miles and still on the original battery (although it was cranking a bit slow during extra cold days last winter).

Anyway, to your question. The climate control settings are linked to individual remotes. Are you using the same remote fob each time, is spouse with you with second fob, which fob is used to open the door? I have found on occasion because both my wife and I often drive together in the RX, sometimes it picks up her climate settings from last time she drove when she's with me even when I've driving.

 

Alas, it happened to each of us once, one key fob each time. Yep, had that issue with the dualing key fobs before, but never had the system start in the full OFF position, no fan, nothing. We do not have Nav by the way.

 

Looks like I found the problem: the "new" Lexus battery was not fully charged. I had only driven short trips so it probably did not charge adequately. Stuck it on a 10A charger for a few hours (and according to the charger it needed a good charge) and all is well. Just FYI in case anyone else has the same issue.