Air con not working

[stefan-west1]

Hi all sorry if this is in the wrong section this is my first post.

I have a 2003 c130 kompressor and the air con is not working. I'm fairly good mechanically as in doing the stuff but not brilliant on how to diagnose the stuff. I've had it taken to a garage to get regassed and it didn't work. As a freebie the garage apparently put some sort of dye in to check if it was leaking but it wasn't. They said they could look further but would have to charge me hence why I'm here.

What could it be and how do I check it? Sorry if I'm being a bit vague

Many thanks

 

[television]

If the led is on, on the control panel then it will need to be activated on STAR, t it will not turn on STAR will tell you what is wrong if anything

 

[stefan-west1]

I will have to have a look tomorrow if it comes on