I had a slightly damaged climate / air con panel in my 2006my 4.2 SC, that originally came with the standard black plastic controls for temperature and fan speed.

I've bought a brand new 07my panel, with the later style buttons. The air con and windscreen prog button are in different positions.

Original unit;
http://i.ebayimg.com/images/g/oNgAAOSwImRYCiZQ/s-l1600.jpg

New unit;
http://i.ebayimg.com/images/g/1AAAAOSwv9FXgNKH/s-l1600.jpg

The issue I have is, the air con button appears not to work all of the time. On start up it may work, but then cease to work some of the time. All of the other buttons illuminate and work as they should. When pressed the air con button is dead, and won't illuminate the small orange light.

I've checked and reseated the two fuses in the cabin for the AC, and nothing's changed.

Has anyone swapped their early-late climate panels around?

Search function appears down, so apologies if there is an obvious answer I've missed.