JMS1868

Can anyone advise where the ambient air sensor is located? Is it in the fender well, bumper, grille? I know the Edge has an ambient air sensor and a climate control sun sensor on the dash area. Are there any other climate or air sensors in the a/c system?

New to the site so thanks in advance.
having several ac issues.

Girlfriends 2009 Edge 200k miles, had issues with blower motor working intermittently. I replaced the blower resistor and it worked fine for two days. Now having same issue. Thought it was a bad blower but it randomly will kick in and blow at high speeds. Also, the compressor will only engage for about a second or two before shutting off again. Connected gauges and it shows high pressure but I believe this is because compressor is not engaging. I added a little Freon but it still will not engage. I also noticed front fan ( I believe for condenser) is running more than usual.

Since this is multiple issues going on, can this be a PCM issue? How can I test, or should I replace the low pressure switch?

Is the radiator/ condenser fan running more due to a hotter condenser caused from low Freon?

I am mechanically inclined but at a loss. Do I continue putting Freon in? I had compressor issues on my truck and after adding a can the compressor kicked on, but is not doing same on the Edge. 
She has the dual climate auto controls.
All help GREATLY appreciated.