Air Conditioning Problems
 

I have a 2002 Saab 9-3 SE Convertible and I have problems with the AC.
When the vehicle is started the AC seems to work ok.
After a few minutes driving the temperature of the AC starts to rise.
At the same time I have noticed that the Turbo Rev Gauge starts to surge up and down from its norm.
And I hear a relay of some sort clicking in and out of contact.
Has anyone any idea what the problem might be and have a solution?
I would appreciate any help I can get.
Thanks in advance.