I searched for "Aux fan" and that did bring up some info about the sensor for the high pressure and the other switch for the temp. Since the fan did come on when I had a bad fan clutch, the temp sensor must be working.
I was'nt aware of the pressure switch on the receiver/drier. (I was wondering why there were 2 switches there though.).
My freon level is a bit on the low side. My low side looks ok 30-40psi but the high side pressure looks to be a bit lower than normal. The range I beleive was always in the 225-275psi range.
I'll jump the switch today, test the fan and possibly top off the r-12. The air could actually be a bit colder as well.