Ac only works on coldest setting.

I bought a 2001 Toyota sequoia SR5 last Fall. I’ve been putting in a lot of hard work into it and I love it. But I can’t seem to figure out why the sequoia will only blow cold air when I set it to 68 degrees. If I set the temperature to 69 the heater starts to turn on. It has not been a priority but the Texas summer is approaching and I need to make sure I have a reliable AC.

 

I had this in a different vehicle, the internal thermostat failed so it only did cold on the coldest setting. Try to find where your cabin thermostat is and if a replacement is cheap, I'd try that. Not really sure how to test if the sensor is good or not. Also no sure where it is in your Tundra. But hopefully this points you in the right direction. I actually had issues finding my part number for mine, and went to a local auto shop and they were very kind and helped me out.