Okay...Another weird question:

When I put the key in my ignition on my 1976 CDeV and turn it to the RUN position...I hear a humming noise...basically sounds like a small motor running or a blower running. Very faint....but loud enough to hear. I was suspecting it was the ATC cycling the vehicle's inside air through the small dashboard vent over the passenger side...:confused:

Just curious.

You are correct - it is the blower motor.

I figured that is what it had to be....the ATC needs to sense the inside air compartment, right?

Whew...so glad it is SUPPOSED to do that!

Hmm Mine did this too, so I diconnected the blower motor because it was annoying me. I guess you wouldn't want to do that since your AC actually works!