I just got a shift ite for my car and was woundering where the tach wire is its a 1987 firebird formula 305 tpi

 

It's the white wire that goes from the distributor and coil to the bulkhead C100 connector and then into the instrument cluster.

A spell checker might help a bit.

Lou

 

Yhea, I wrote that in like 10 seconds. I was in a rush. Uhh out of what you just wrote what is a c100 and a bulkhead????...Ya im still learning as your can tell...What wire is it???

 

C100 is the 46 position connector that goes thru the firewall on the driver's side. The white tach wire is in position D6, which from the inside would be the fourth row from the top, third position from the left.

 

Hmmm..okay. lol..
I have no clue what any of that means.
Could you just tell me what wire it is???
Sorry im still learning about cars.

 

I assume you'd want to connect the shift lite somewhere under the dash. Just remove the knee panels under the steering wheel and look up into the dash. You'll see a connector going into the back of your tachometer (it helps if you lie on your back with your head by the pedals). There will be a WHITE wire in the bundle. That's what you're looking for.

Hope this helps.
Lou

 

Ahh cool got it now. Thanks it works now.

 

 

To clear things up for future reference:

C100 = Connector 100, a label assigned by GM. They label every electrical connector in this manner. C100 passes thru the firewall on the driver's side. The inner or passenger compartment part of C100 is attached to the firewall. For this reason it is called a "bulkhead connector." C100 has forty six (46) positions, cavities, or places for wires to go. There are seven rows of these cavities. These rows are labeled A thru G, from top to bottom, i.e. the top row is labeled A, G is the bottom. There are several cavities in each row. They are numbered sort of oddly. Looking at C100 from inside the car, row A, from left to right, is numbered 4,5,6,7,2,1 (there is no 3 on row A). The white tach wire goes to D6 (row D, position 6). Row D is the fourth row down. From left to right it is numbered 4,5,6,3,2,1. So, D6 is the fourth row down, third from the left.

Every decent schematic will show all connectors along with their labels. Each wire on the schematic will show the terminal it goes to on each connector (such as D6 on C100). Most if not all connectors have numbers and or letters molded into them to identify the positions. Factory service manuals, unlike the cheap ones, will show you end views of every connector (drawings of what the connector looks like from the business end). They also tell you component locations and have drawings of these, including wiring harnesses. They are well worth the price compared to manuals such as Haynes, which are rather generic. I have one for almost every car and motorcycle I've owned. I've also found GM (and other) dealers to be very accommodating when is comes to allowing access to their service manuals. The hardest time I had was with one place where the service manager had to get the manual for me, every other place just pointed to their library. This has been a great help when I've been on the road without access to my own library, or before I've bought my own.