GM Vehicle security system100

Hey Everyone I have a GM Good Wrench Vehicle Security System 100 circa 1988. I have recently acquired the installation instructions but found the instructions for programing the 3 digit code were not included. Apparently it was a accessory module that was not part of the basic system. Does anyone know how to program the key pad? (looks just like a telephone key pad) Thanks a million. :confused:

might want to ask this question in one of the GM areas on here