There is a buzzing sound which appears to be below the glove box when I have the FRESH AIR or RECIRCULATION buttons turned on. I know the blower motor is located there but it doesn't appear to be that.
If neither are turned on then the buzzing noise stops. (You can still have the blower going without either of those buttons pushed) Just wondering if this could be a faulty relay or something and where exactly it might be located?

Sometimes faulty vacuum servos like those used in heater controls will often buzz when the diaphragm goes bad...

Sounds like it's probably the one that controls open/close of the fresh air door...you'll have to pull the lower cover off the dash and try to isolate it probably...I can't tell you where it is (other than close to the heater/a/c cores...)

Could be electrical too, like you said, but I'd check the other first...look for vacuum lines in the heater control and plenum locations, try disconnecting or pinching and see if the sound stops, then follow to the problem servo...

I know this is an old post, but does anyone have a diagram or more answers for this. I have the same problem on my 91 EX and need some ideas how to fix, its stuck on the recirculation position and my windows tend to fog often.