ok,on my -70 cuda theres a hole in the firewall,just above or under? the road-lamp grommet coming into the engine compartment.anyway you will see witch hole it is when you look into the engine room as your missing your harness,i have not looked closer into where it routes under the dash,but believes? it goes straight to the b-u lamp on the dash.in the engine compartment side on my car on the firewall is a barrel shaped grommet with the b-u cable sticking out of it a few inches with a connector on it,witch then connects to something,maybe the single connector cable coming from the wipermotor cavity in the connectorthing on the firewall.overandout