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SESK: Stuff Everyone Should Know · sesk.info/cdl-compressor-governor-cut-in

At about what tank pressure does the governor let the air compressor start pumping again?

About 100 psi, the cut-in pressure.

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  1. About 60 psi
  2. About 150 psi
  3. About 100 psi ✔

Why: When tank pressure falls to the cut-in pressure, around 100 psi, the governor lets the compressor pump again. Check the maker's specs for your truck.

Huh, didn't know that: To test cut-in, idle the engine and step on and off the brake until the gauge starts to rise.

The dad joke
Why are air compressors great at parties? They know when to cut in.
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References

Answer: About 100 psi. When tank pressure falls to the cut-in pressure, around 100 psi, the governor lets the compressor pump again. Check the maker's specs for your truck.

  1. Texas Commercial Driver's License Manual (DPS) www.dps.texas.gov/internetforms/Forms/DL-7C.pdf
    Pumping by the air compressor should start at about 100 psi and stop at about 125 psi.
    Checked 2026-10-10.

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