I don't remember either of my IACs making a noticeable noise.
It turns out to block the air passage, then backs back in to a certain point when the key is turned on, then when the system is in closed-loop, it makes minor adjustments to keep the idle within a certain range.
You could remove it, but leave the electrical connector hooked up, then turn the key on and see if the valve cone (couldn't think of what to call it. LOL) screws out, then screws back in a little. If it just clicks and doesn't move (acts like it's stripped maybe?), then it needs to be replaced.
Also, while it's out, make sure the valve cone is clean and see if there's a bunch of carbon in the port in the throttle body.
If you start the van with the IAC removed from the port, it should idle high (like it has a vacuum leak).
If you stick your finger in and block the port, the idle should come down closer to normal.
If the IAC moved like it was supposed to, then maybe try the relearn procedure and see if that fixes it?
Just disconnect the battery long enough to for the ECU to lose its memory (a couple of minutes or so)...
Then reconnect it...
Jumper the A & B terminals on the diagnostic connector (Like you're going to read the codes by flashing the check engine light)...
Turn the key on (not to start) for about 30 seconds.
That should make the IAC plunger back all the way out to find its base setting.
Then turn the key off and remove the jumper.
There's more to the entire process which involves setting a base idle and some TPS stuff, but the steps I mentioned should get the IAC to zero out, so that it has a solid starting point.
If you have to replace the IAC, you'll have to do that same procedure on it so the computer doesn't use old settings on the new part and the new part will start at zero.
Dang! Did I really just type all that?