I know what's involved.

Last March I tracked a lack of tach display to the white/red wire in that harness under the strut tower. In order to repair the chewed wire I needed to pull the harness back toward the firewall. This one goes all the way to include the horn wires. I could not finagle the end past the left headlamp without removing the bucket.

In the past I've been able to use a cutoff wheel on a Dremel to get through the rust and replace the bolts with stainless, but in this case the lamp's adjuster plastic parts were broken before I even started.



Gave me an excuse to buy a set of aftermarket lamps. New lamps really improve the looks of the car, an 89.



You might try a little harder than I did to avoid pulling the horn wire through; I just hate to cut and splice a wire in that corrosion-prone area of the car.
--
Art Benstein near Baltimore

Why are a wise man and a wise guy opposites?