Guys, trying to fix my AC/heat, over the.

Hi guys, trying to fix my ac/heat, over the summer my car ac started acting up. When it was really hot outside my ac wouldn't come on even tho the display shows the ac on max. As in temp 60 degrees blowing at max, yet nothing coming from the vents. If while driving if hit a bump r pothole, the ac would in fact come on. Sometimes as soon as I turned the car on the ac would work, but not always. Now that its gotten colder, same thing with the heat, the display shows 90 degrees blowing at max but nothing, sometimes if I hit a bump it comes on, sometimes it doesn't, sometimes it comes on as soon as I start it. Any idea. These 38 degree morning rides to work r killing me. Lol thanks guys!