It's a good idea to install a relay to not get the full current on the switch. Also You may be able to disassemble and clean the contacts on your switch depending on what's wrong with it. I have done this successfully before. DL
Year One sells a reproduction switch, but I don't know how it compares to the original in terms of appearance. I searched high and low until I finally found an NOS switch for my 71 GS on ebay last year.
Link to relay thread discussion plus a few more ideas on the relay setup I designed for my car. Might be helpful once you find your replacement switch. http://www.v8buick.com/showthread.php?241826-Convertible-Top-Relay-install Later Tim