Newbie-1992 300d a/c question

[jobadiah]

Longtime surfer, but finally just registered. Several months ago I finally got my first Benz, a 1992 300d. I've been very happy with it. I have an intermittent a/c problem and yes I have done some surfing on the forums but I'm still a little confused. The guy I bought the car from always had the Benz dealer do the work and he had receipts of about 3K to 4K$ of a/c work done recently-most of it was switching to 134a. It usually either works or doesn't but sometimes it works at first and then stops blowing cold(yes it always blows so the fan is good), so I'm thinking it's something electrical. I'm pretty mechanical and was wondering about the relay bypass fix-can that be done the same way on my car since it's a '92? and is it recommended? just wanting some more input. Also I got the maint. cd's off ebay and was wondering if someone had a list or site they suggest for basic maintenance and such.
Thanks.
Jobadiah (in Georgia)
(thanks for the title-post response)