I have this detail on file and thought it would help.

After the harness comes off the trans, it goes through one black plastic circular shaped wire strap on the firewall.(this is on a 73...I think earlier years used a either a black or white "D" shaped strap) From there it runs accross the firewall and connects to the lower lefthand corner of the bulkhead connector. It only goes through the one strap on the firewall...the one below the voltage regulator. If you want me to take a pic let me know.