Air Conditioning problem
2003 Chevy Suburban 6 cyl Four Wheel Drive Automatic 70,000 miles

Bare with me, I know nothing about cars....

Last year the rear ac/heat blower stopped working, i was backing out of the driveway and was pushing on the floor with my left foot and the blowers just came on. they stayed on for a few minutes and then shut off. Again if I push just right in that area where the floor and "step board molding of the door" come together I can get it to briefly come on.

Please help!

Thanks
Natasha