Tire Pressure Lights and Tire Pressure

[Iceracer]

Easy thing to prove out. Light comes on, check the pressure with an accurate gauge.

Another thing to consider is when are the pressures checked ? When the tires are warm from running or in a heated garage ?
Or in the morning when the car has set all night outside.
Lets say the pressures are check when warm. Set to 32 psi. Then in the morning the temperature is below zero. The pressure has already dropped significantly. Say the tire was 50 degrees F when checked. At zero, the pressure could be 27 degrees.
Again, the whole thing is easily checked.

[Mustang Man]

Also the tire stick lists the cold pressure, this pressure is what the tires should be at when cold. They will then heat up and increase from that point not to be set at the warm temperature to then cool down and become underinflated.