I'm getting an odd sound from inside my dash. Its like a click/tap. Its loudness and frequency are related to what setting the ac is on. off- loudest, 2 second evenly spaced intervals. ac on high- quieter and 3-4 second irregular intervals. It started when I took out the factory stereo. Today I pulled all that out and unscrewed the panel underneath the stearing wheel trying to find the source of the noise. Its coming from somewhere deeper in the dash in between these two areas. I plan on doing a bit more searching in for the source of it today when I have some more time. Any suggestions or ideas you may have would greatly be appreciated.

 

Probably one of the vacuum actuators flippig the vent controls rapidly. My guess is that it would go away if the controls were all the way hot.