The governor controls:
Correct. The governor cycles the compressor: it cuts the compressor in around 100 psi and cuts it out around 125 psi.
CDL Practice Question #99
Category: Air Brakes
Why this question matters
This question is one of 71 in our Air Brakes bank. The reasoning above comes directly from the AAMVA CDL Manual, the source document used by every U.S. state DMV. Memorizing the underlying rule — not just the letter answer — is what separates passing on the first attempt from a return trip and another fee.