installed an OEM tach/clock combo and am trying to fugure out if the wire for the tach is already ran in the harness. Mine originally came with idiot lights but the wires for the H20 and oil pressure sensor were already ran and just tied off. I have located a WHITE wire with a male spade plug that is not connected to anything in a harness on the firewall near the brake booster. I have seen some G-body wiring diagrams that say the underhood tach signal wire is white and others have shown it as brown. Can anyone confirm? Also if I can't locate existing tach signal wire under hood will just run a wire from ign box to underdash, anyone know where the white tach wire is located under the dash? I really don't want to pull the entire cluster again just to catch the wire at the dash plug.

thanks, I wish I could have found that last night when I searched :( So I pulled the dash again (always hate to because the plastic is so brittle) ran a wire from the post with nut labeled "coil" directly to my 6a box for the tach wire. Nothing, went back to the parts store and spent $50 on a tach adaptor and the tach pegged 6 grand and stayed. Went to work and grabbed a used Autometer monster tach to test tach signal and the autometer works like a charm. Looks like I have a bad tach. While fishing around in the engine compartment I did find a brown and the same white wire, they both had male spade connectors on them, I wonder why GM would have included them in their harness with a vehicle that had lights but not pinned the connector at the dash if they knew it wouldn't have a tach? :? I guess those same engineers went away when the Elky disappeared and made room for new screw ups :)