I'm putting a Sun tach in my 90 silverado. does anyone know the color of the dash light wires so I can splice into it?
If that was too easy.... how the heck do you change the bulbs in the instrument panel? I pulled the cluster out but it's got a warning on the back not to open it.
thanks!  

Its the gray wire in the radio wiring harness. you can find it inside the dash by removing the radio. Here's a link to a great source of info:
http://www.the12volt.com/installbay/stereodetail/472.html

hope this helps.  

Take the glass cover and the black guage cover off, there should be some screws holding the guages down, unscrew all of those, pull each guage strait out, dont twist or try to turn, all the 194 bulbs are there to change, put really good LEDs and they'll even be brighter