the donor was a 2001 gmc somona 4.8 2 wheel drive-------yes i cut some wire from the s10 system but i dont think that i cut any from the speedometer4.8 is a newer communication system.It uses CAN or control area network.
The 95 may or may not be CAN.
The 4.8 electronics will send a completly different signal than the 95 as the 95 would most likely be a pulse modulated signal, like a square wave or sine wave,unless it is CAN also.
You will need some type of converter that will read a CAN protocal message and convert it to a pulse.
The only other option would be to tap into the vehicle speed sensor at the trans, and wire it to the speedo input at the cluster. I would have to research the wiring diagram for the 95 to see if the speedo processes the speed signal or if it is processed in the PCM.
If the 95 used the speedo to process the speed signal, then it could be as easy as splicing to the VSS at the trans and maybe putting a signal amp on it, as it may not have enough output to run the new PCM and the speedo.
I will need to know what the vehicle is and the donor vehicle is, so I can check system configuration and check wiring schematics. it may be as simple as moving a few wires around in the newer donor car harness, or splicing 2 wires at a different location.
Did you have to cut any wires from the old harness when installed the new?
Also what was the donor vehicle?