737-300 ram air door
737-300: what is the purpose of the "ram air full open" light. We know it is full open on the ground, and full open in the air when the flaps are extended. And from what I have read, the door will "modulate" as necessary in the air with the flaps retracted, and I guess this is when the "fully open" light will annunciate. So, 'whats the significance' -- Question no2: Pre-cooler control valve leading off from the 'fan air'. Is it ac or dc, and how does it function ? ---btw, this my 1st post, am not an ATP, am retired, have had 4 hours in the sim. I spend alot of time studying the 737, which I find to be fascinating, and am very much appreciative of you folks, sitting up in the front . I worked in a refinery 26 yrs, and am familiar with flows, psi, hydraulics, pneumatics, electrics , and am slowly figuring out how all that stuff on the overhead panel works( thanks to internet, videos,cbt, etc etc).- now about that "ram door"---