overhead console in sierra?

What year did the console come from? I'm not sure the OBD I Blazer/Jimmy twins had an OHC with trip computer, they may have only had the compass/temp. Even so, the data bus may be set up different and this may be tough to wire up. I know the newer S-trucks have at least one junction block with open terminals to connect into the data bus, I used this to hook up my OHC (99 Blazer console in a 2000 S-10, so that made it easier).

I'm not aware of a wiring harness for your specific application. Even if there WAS a spot to tap the data bus, if your truck even has one, the S-trucks and C/K trucks MAY have used different signals on it, so the signals may get crossed so to speak.

Can't help ya on the wiring diagrams, sorry.

Can't recall what year it's from. Trying to get ahold of the guy I got it from to find out.

Still not having much luck on wiring diagrams, but if I'm understanding my google finds correctly, if it's 97 or earlier, I might be able to get the trip computer to work by connecting it to the VSS? (Looking at my Haynes, maybe tap into the speed signal for the cruise control or RWAL at the convenience center under the dash? Get serial data from pin E on the ALDL?)

Again, the wiring is a little fuzzy here. Especially putting an S-truck console into a C/K truck. Yes, 98 was the first year for revised wiring on the second-gen S-trucks. The part I'm a little skepitcal about is that your truck is an OBD I truck where the truck the console came from is OBD II.

My wiring was real simple, had a harness put together, but there's that issue of the wiring differences between the S-truck and C/K truck. My VSS signal came from behind the radio. Find a good automotive electrician with access to the right diagrams and they might be able to hook it up.