Digital air conditioner not showing temperature?

I just got a used Maytag 6000 btu air conditioner, it's model number M7X06F2D-A i paid $60 for it...and it's digital and has a remote - i went on the A/C and put it down to 66 (lowest it goes) but it's not cooling off my small bedroom....and it's staying at 66....i have a digital A/C in my livingroom and when i put it down to the lowest it goes, it'll automatically after go to the current temperature and then you'll see it going down slowly....like i have it set to 60 (lowest) and it currently is displaying 72....but the one i just got, it's not changing it's just staying at 66...and it's not 66 in my room or else it would be cool, and it's HOT in there.