Question:

What is the best way to test your vehicle's low air pressure warning signal?

A Step on and off the brake pedal with the engine off to reduce air pressure below 60 psi.

Explaination

Turn off your vehicle's engine while leaving the electric on, then step on and off your brake pedal to test the low air pressure warning signal. When you lower the pressure below 60 psi, the low pressure warning signal should appear. You should never have to go below 30 psi.