Get to the blower motor in your Tundra by unscrewing the glove box and pulling it out. Unplug the electrical connectors and unscrew the motor and fan.
Check the coolant levels. The coolant reservoir is found under the hood at the very front of the vehicle.
It is white and plastic. Open the cap and shine a flashlight into the reservoir. Make sure the coolant level is less than the full line but more than the low line.
Adjust the climate controls. If they do not feel right with the correct amount of resistance and pausing in the right locations then the problem is probably the control panel. Getting to the control panel in a Tundra is very difficult, and will probably need to be done by a mechanic.