Fan Cycle

[Nilao]

My engine fan will come on once my air pressure falls under 90 psi. I chased it for weeks trying to figure out why it was cycling every time I pumped my brakes coming down an off ramp or backing into a dock. Come to find out the ecm was closing my air solenoid at 90 psi. The root cause was my air governor was out of adjustment causing the compressor to not kick in till 90 psi. Once I replaced it the issue went away.