The brake audio and visual air pressure indicators should turn off at about ____ to____ psi.

The brake audio and visual air pressure indicators should turn off at about ____ to____ psi.

• A. 60-65
• B. 80-85
• C. 70-75
• D. 90-95

Answer: (B)

Air brake systems use a low-pressure warning light and buzzer to alert you when pressure is dropping. Once the system pressure climbs back to a safe level, the warning should turn off. That safe threshold is typically around 80 psi (often specified as about 80 to 85 psi for the shutoff). So turning off in the 80–85 psi range matches the point at which the system is considered ready again for normal braking operations. The other ranges would either keep the warning active while pressure is still low or wait until pressure is higher than needed, which isn’t how the indicator is intended to behave.

Air brake systems use a low-pressure warning light and buzzer to alert you when pressure is dropping. Once the system pressure climbs back to a safe level, the warning should turn off. That safe threshold is typically around 80 psi (often specified as about 80 to 85 psi for the shutoff). So turning off in the 80–85 psi range matches the point at which the system is considered ready again for normal braking operations. The other ranges would either keep the warning active while pressure is still low or wait until pressure is higher than needed, which isn’t how the indicator is intended to behave.