Look for a blown fuse or bad relay for the a/c in the front fuse box. If replacing fuse and it blows again, then there is a short circuit on the load side of the fuse which goes to the a/c compressor clutch. If fuse ok, try another relay to replace the possible bad a/c unit. The engine computer controls this relay. It also receives air temperature sensor reading from cold air path.
Describe your 2000 Chrysler Town &amp; Country Problem - the a/c button doesnt work to turn on the compressor - can i replace the switch or the whole head unit