Has anyone had any issues with their windshield wiper motor and / or switch on a 1975 Corvette?

I have replaced both, several times with different vendors.  Each time they work well for a short time and then quit.

Any suggestions will be much appreciated. 

Hello, I firmly believe it depends on the vendor and country of origin. If it doesn't have GM on it, or made in U.S.A. I would look for some that do. Especially if the letters are R. O. C. or any with a K. also in the acronym. I tried brake light switches from said vendors,  and like you, they lasted long enough for me to take a trip and return home. Got a GM one, and it's still operating.