I had the AC recharged at the dealer; a dye test was done at the time but didn't indicate location of leak. Three months later it didn't work and it was recharged again. Superficial tests for leaks at all the places that were easy to access didn't turn up where the leak was. (No dye test done this time).
The mechanic suggested it could be the evaporator was shot.
My question is this: what needs to be done to definitely diagnose the location of the leak, and what are the chances it will require replacing the evaporator?
Any suggestions on how to approach getting this diagnosed would be appreciated. Thanks. Terry