My A/C didn't work when I got the car: Didn't blow cold. I got a manual, educated myself. Checked out all the components, found a fuse blown in the relay that energizes the low speed fan. Replaced the fuse and checked for low speed operation of the fan: It worked and the fuse didn't blow. But the A/C compressor still didn't come on: Found a relay that controls the switching-on. It costs $135. I'm cheap. Took the relay apart. Two little relays inside. Opened one up. Actuated it with finger. It made good contact. Installed everything. A/C worked like new. That was two month ago. It's still working. You can do it too.