If a red warning light appears on the trailer service (yellow, diamond-shaped) valve, coupled with a loss of air pressure on the secondary gauge, what specific issue might this point to?

Question: If a red warning light appears on the trailer service (yellow, diamond-shaped) valve, coupled with a loss of air pressure on the secondary gauge, what specific issue might this point to?

Answer options: ✅ A severe air leak in the trailer's service brake lines.

• The trailer's anti-lock braking system has failed completely.
• The tractor's parking brake is accidentally engaged.
• Over-pressurization of the trailer's air tanks.

Correct answer: A severe air leak in the trailer's service brake lines.

Explanation: A red warning light on the trailer service valve combined with a loss of secondary air pressure often points to a severe air leak in the trailer's service brake lines, as the secondary system typically powers the service brakes. This requires immediate attention.