The 94 and 95 Bonnevilles are OBD1, with the OBD2 connector and codes. A 96 reader will not work.
You need a 16 pin connector on a reader capable of reading not only OBD1, but specifically the 94/95 Bonnevilles. My scantool (Actron) will work with the right cable, but my connector is a 12-pin. jr's3800 has a 95se, uses the same scantool I have (I bought mine on his suggestion) and he has both cables for it. He can read 87-95 PCM'*, I'm limited to 97-93.
We have a scantool registry in Techinfo. Someone might be close to you.