Brown mystery wire??
 

Im re-doing some of the front harness wiring in my 1969 oldsmobile delta 88. Theres this brown wire that comes out of the firewall bulkhead. It has a push on terminal that looks just like the fuel sender wire. Im at a loss it looks factory and its not very long, maybe for underhood lighting? Any guesses are welcome
https://cimg7.ibsrv.net/gimg/oldsmob...ad5c27822.jpeg