Below are two pictures of the one I installed on my 96 Caprice. It was out of an Olds Bravada. The S10 Blazer/Bravada and the Astro all use the same center section, but the trim base were it meets the headliner is shaped different between the two. It doesn't really mater which one you use, because this section of the trim is set up inside of the headliner anyway.
The displays that will work with our cars are from vehicles that are 1997 or older models. After these years, the displays use a data link to comunicate with the vehicles PCM and the PCM's on are B-Bodys are not set up for this.
An easy way to determine if a display will work is that if it has an "on/off" button just to the left of the display and NOT a "Mode" button in that same spot.
The Mode button selects the features of the fuel computer which will not work with our cars.
I believe that the correct display also has 6 wires coming out of it. I'm doing this from memory, so someone correct me if I'm wrong about it being 6 wires.
The wires for the display are basic for 12volts for main pwr, dash light dimming, wire running to outside temp sensor (usually mounted behind the front grille) and a wire the splices into the "speed sense" wire so that the it only takes temp readings while the vehicle is moving so not to get false high readings from the radiator when stopped. The vehicle speed sense wire can be spliced into were it is running to the factory stereo (not sure what years, 94-96?) were as the factory stereo has the speed compensated volume feature.
If anyone has a correct on/off button display but with a damaged console, I may be interested in buying it. I have a one of the short mini consoles made for a blazer with a sunroof but it is a newer one with the mode button. I grabed it anyway for the possibility of finding another display later. The mini consoles are nice if you want to cover a ticket light hole, but dont want to cut up so much of your headliner. The one I found is grey and has map lights and the homelink remote buttons and ofcouse the open close button for the sunroof, but it doesn't have sunroof written on it and works as a momentary contact switch that can be used for anything.
in the bottom right of the above picture is the temp sensor that mounts behind the grille, if you find a console in a salvage yard (Astro,Blazer,Jimmy,Bravada) then remember to get the temp sensor off the same vehicle so it will be calabrated the same, were as the temp sensors from the Roadmasters are not the same and will give a false reading when used with these overhead consoles.