Strange intermittent vibration/chatter/noise behind dash

I have a '95 Riv SC.
I need that sound effects guy from the GEICO commercials to reproduce the sound I am hearing behind my dashboard. I am fairly sure it is related to the dampers/regulators (or whatever they are called) for the climate control system. It is like a combinations of a semi-squeaky chatter and vibration that lasts for a few seconds at a time. There might be a series of a few of them and then it will go away - sometimes for days - sometimes for hours - sometimes for minutes. Other than the strange noise everything seems to work just fine. I typically do not use the AUTO function of my AC system. I usually just put it on 60 degrees and use the fan speed accordingly. Sometimes I will adjust the temperature, but will always control fan speed manually.
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My Rivi also talks to me sometimes. I don't really mind it, my fiancee thinks it's funny.

There are five actuators under the dash, even if you don't use the "AUTO" mode they have to move to get the air to the right place at the correct temp.
It is either one of these three or one of the two on the passenger side:

99Rivman wrote:

Thought I’d put this out there just in case anyone else is having problems with their HVAC.
The first picture is of the driver’s side of the HVAC Module Assembly and the actuators that attach to that side, there are two more on the passenger side. The three on the driver’s side are the same part number and the two on the passenger side are the same also but they will not interchange from left to right. If you have problems with the air mix to either the A/C or Defrost or Heater these actuators are more than likely your problem.
The actuator has a 5 volt motor in it that turns gears that open and close the air mix doors. I had one that had gotten stuck on my first Silver Arrow and was able to free it up and it has been fine ever since. I was having problems on the new Silver Arrow, air wouldn’t go to the heater vents, and that was what I was looking into. After removing the left sound insulator I found out why! Some idiot had removed the #3 actuator in the picture and the air vent! Luckily they are the same for all years of the Riv so I was able to replace both parts with parts from my spare ’95.


The actuators are listed as follows:
1 Defrost Actuator
2 Mode Actuator
3 Air Mix Actuator

This is most of the write-up but the rest can be found here:
https://rivperformance.editboard.com/interior-f20/write-up-hvac-assembly-t2500.htm