Can't enter programming mode

I just bought a used 1994 Jimmy. I contacted the dealer and found out that the vehicle came with keyless remote. I have tried to ground the purple ( lower left ) pin. I also have tried to locate the red wire that a thread for a 1995 referenced.

Welcome to AF, try this hold the lock and unlock buttons down together till the doors lock, then see if the program works.

Tried it, nothing.
Thanks