1998 gmc c/k overhead compass

I am working on a 1998 gmc  fullsize pickup, it has a overhead console. These trucks console has a block off plate where in the suburbans has a rear air control. The s-10 Blazers have a similar overhead console with a digital compass and Temp readout in this spot.  After getting one from a donar 98 blazer I found it fits perfect. I also got the harness and Ambiant air temp sensor off the blazer. I have the wiring diag too. I have everything figured out except the VSS wire.

The Vss is listed in the Vehicle wire diag lists driver kick but no color given just a pin out given. Both are 4k pulse on blazer and full size so it should work fine. But where can find this vss wire? Dont some of the gm's have a vss in radio harness? They adjust the volume by speed at the radio?

Thanks.

I mounted the ambiant air temp sensor in the exact location as it was on the blazer.  I know that they are both 4k vss. But the vss wire at the radio is not a true vss circut. It is motified for the raido auto volume control, I pulled the gm diag from alldata pro and it only increases voltage in incraments of 10mph, so the vss at the radio is not a true vss.  also IT IS nessess the VSS tells the computer when you are not moving so don't update the temperature.  I tested both ways. The Temp NEVER CHANGES without the VSS without power cycling the unit. With true vss wire,  (wifes gtp used as test because its easy to get at)  and air temp sensor in vent to test temp change , it changes immediately with temp change. Her car has digital read out for the climate control and it is perfectly accurate and changes with the climate display.   So this leads me to belive because I am not using a true VSS  in the 98 gmc it is much slower updating . About 10 times slower to be exact. LOL     I am going to pull the cluster sometime this week and run my wire to the vss wire that runs the speedo, That has to be a true VSS.

Any other ideas?