Tach signal wire problems

[Racer57]

Have had my gauges out to replace what I thought was a bad tach.  Installed a new tach and while everything was out, decided to send everything to Redline for the amp to volt convert.  Got everything put back in and the tach still did not work.  Finally figured out that the signal wire is not working. There is no continuity from gray wire at coil to the black wire at tach. (Before you say anything, its the same wire thats always been used).  I'm assuming the guy that had the car before me spliced the wire and did not stick to color code.

Here's my question... Wire at coil goes into harness and wire under dash goes into harness.  Does the tach wire go through the firewall connector ? I'm assuming theres a break at the connection between the gray and black wire and wanting to repair it. Harness has been re wrapped.  I'm about tempted to run new wire and find someplace to get it through the firewall.

[TelisSE440]

Hi Racer57, yes it does go through the bulkhead connector, i have attached a part of the wiring diagram (the ''20'' slot). This is the side you see in the engine compartment.

[Racer57]

Thanks ! That helped me find the problem !!!!!!!!!!!!   
I pulled the fuse block out of the way and immediately saw a black wire hanging loose. Checked continuity on the block with a jumper and that was it !!    Now I'm going to find a gray wire and fixed the damn thing the way it was suppose to be !! 

Gawd I love this forum !!

[TelisSE440]