2014 Lexus ES 350 temp settings change randomly

Purchased used w/19,800 miles. The temperature settings randomly change, both up and down, drivers side & passenger side. It is not the dual setting mode. Lexus wants $175 for diagnosis even though there is some warranty left. Any ideas?

Not sure what warranty you think is still left. The Lexus warranty is for 48 months or 50000 miles. So all that is left is the emissions and drive line .
That diagnostic fee is high but this is a luxury vehicle so not out of line . You did not say how long you have had this or where you purchased it from. If a dealer you might call and request some help with the repair .

Randomly changes while driving?

Or the next time you start the car, they have changed from previous setting ? Could be dirty battery connections or a battery that is on it’s last leg, causing major voltage drop when starting engine.

If it was a CPO car the warranty could be extended by as many as 6 years.

Or, it could be a symptom of a failing alternator.