Am I going crazy?Cicking sound

[Z-71]

It's a 03 5.3L silverado ext cab Z-71.Just last night when I was letting it warm up for a couple of minutes I noticed a clicking sound (sounds like a solenoid is turning on) about every 30-45 seconds and thought wtf.Today I looked into it and it turns out that it is my ac pump...everyone around here says it is completely normal when you have your defroster on or the ac turned on but I have never heard the sound before.And on top of that my mechanic friend who has the same truck just with more miles couldn't get his truck to make the sound...he said it was because his freon is probably low.But I think if his freon is low/gone his should make more noise than my working ac system.Shouldn't it?Please help me.Is this normal like everyone is saying?

[u1arunit]

Yes it's normal for the clutch to click on the AC compressor when it engages with the AC or defrost running.

It not clicking in because the refrigerant is low is prevented by the pressure switch in the system.

He is correct on both counts.

[Z-71]

Okay thanks,I really don't know how I have missed hearing it for so long.I guess it will just end up being one of those sounds that drive you nuts but at least nothing is wrong I suppose.