AC pump turning on and off
 

I noticed the other day after installing my Crawford AOS that my AC clutch pulley turns on and off/catches every 15~30 seconds. It creates a thumping noise that can be heard. I keep wondering if I messed something up while installing the AOS. I went back to double and triple check that the belts are on track, wiring plugged in, and ac pump bolts tighten. The ac clutch pulley does not catch unless the HVAC is on. I have not tried turning on the AC. Anyone have this issue?

If you have your selector set to anything that includes the windshield, AC will come on automatically. This may be what is happening.

It's normal for the system to turn on and off.

You changed the size of the pull. Now it does this more often.

That' normal a/c operation