OK, so I am posting this a year later for anyone having an intermittent A/C problem.
I drive a 2016 TC XLT and within the past 6 months, (I live in Florida so I use A/C in December), began having a problem where my A/C would suddenly just start to blow warm....a few miles further and it would work normally again. This was totally unpredictable and no amount of fiddling with the controls would would have any effect.
After a major internet search, which included this thread, I decided to change out the ambient air temp sensor since It was only $16.00 at NAPA. On my vehicle it was located exactly as shown in Zalienz's post above. The view shown there is from the inside out after the plastic shield has been removed...this puts it on the driver's side in the lower corner of the cowl. I also took this opportunity to replace the push rivets on the underpan which were damaged or missing from oil changes.
The fix worked perfectly.