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yeah but you don't need both. If the copper trace is patched that added white wire is redundant. And like I stated before... if that added wire repair suits you, solder it to the new IVR and forget patching the copper trace. Some inst' panels ( e-body for example ) don't have circuit boards. Actual wires were routed to everything.
I wont retract everything I've suggested thus far because there are so many different ways to approach a problem, different ways to patch a crack as it were.
I do tend to study, weigh the facts, before deciding what I think is the best patch.
So first the facts... This piece of white wire that someone added. Please confirm for me what color factory wire it is attached to. My background knowledge suggests blue with white tracer. Regardless its color, I know this power comes directly from your ignition switch. There is no fuse between the ignition switch and the inst' voltage limiter other than the spot you have burned open. At this point I will mention that later model builds do get this power through a fuse.
You have a inline fuse holder pictured there that really should be removed.
The part stores have a big yellow butt connector from Dorman that includes heat shrinkable sleeves. One of those and a good crimp tool is all you need to propely connect the big red to black.
You could use the inline fuse to bridge the burned open trace. If this was my car, my chore, I would add enough wire length to have this fuse holder in a more favorable/accessible location and I would label the fuse holder, IVR-5A.
Honestly... I would clip the blue with white tracer out of that harness connector and attach my wire and fuse holder wire to wire. This wire doesn't supply anything more than the limiter on the panel. We'll bypass that connector and contact pin too.
I would also solder the other end to the center springy female terminal on the circuit board rather than soldering onto my brand new regulator or on the copper trace. Why? There is a downside to soldering long wires on top of the copper trace. If the wire should get pulled, it would peel the trace right of the board. After I soldered a piece of wire onto the female clip where the regulator plugs in I would cut it somewhere to have a male/female disconnect. This so the panel does unplug for removal just like it did before I started.
So there... I've over thunk this thing as if it were my own problem to solve. It has kept my mind off of other things though so thanks for that.