I cannot select the recirculate air feature on my ED 6cyl for just inside air on it's own..

When I press the recirc button the A/C comes on and is in recir mode BUT if I press auto off then it goes to fresh air mode..
I did what I believe to be the "diagnostic test" by ignition on and pressing the off/foot buttons on the A/C(at the same time then letting go) and then the display panel lit up for say 10sec then nothing else happened...

Also,how can I test the coolant temp sensor located in the thermostat housing? My guage shows 1/4 ALL the time but I am sure it must be more than that..

Many thanks in advance!