Would Like Advice for Troubleshooting Wiring

Just bought a 94 Buick Century 3.1 liter V-6 which ran fine. Still I changed the plugs and wires and now my "check engine soon" light comes on with multiple error codes including the crank position sensor.

Since the plugs and plug wires are difficult to get to and require removing the coil pack assembly and disconnecting lots of wires, the wiring seems to be the obvious culprit. I have also repaired many small vacuum leaks, but don't believe that even a large leak would cause so many error codes.

Alas, I have checked all the connections and plugged/unplugged them multiple times. I am afraid that either a break. loose connection, or corrosion is where I cannot easily find it.

I am very open for advice on either locating the problem, bypassing the problem, or perhaps looking for a new engine harness assembly at an auto salvage yard.

Found problem!
There is difficult to find group of inline fuses that can only be accessed by removing the glove compartment and fuse block. Even with diagrams and a photo from the shop manual (which showed the old style round fuses instead of the bayonet type that were in the car), I went back and forth the diagrams and car 3 times before finally locating the blown 10 A fuse.

I then cleaned up the mess left by the last shop that tried to troubleshoot the problem before I bought the car and all is well (with the wiring anyway, grin).