Check Engine Light. Eternal long lasting. Need knowledge.

[89ARIES]

My car now has codes 12,31,32,37. All have to do with electrical issues. I am at a 100% loss. Bill, Butch, and I cleaned connectors and confirmed yesterday
that the selenoids are working. Here is what I wish someone here could explain to me in layterms:

1. Can a mechanical condition trigger confusion in the computer thus resulting in a stored code?
2. Does the computer control the engine or the engine the computer?
3. The computer has had chronic check engine light codes since 2008. It is a never ending saga. NOTHING I have tried has stopped it from throwing codes.
4. How does one fix an OBDI issue without throwing parts. YOU CAN'T! Track this wire, clean this wire, etc, etc, etc. The only thing I can see is just to do
a massive $1500 electrical overhaul and replace every single strand.
5. Its impossible to check wiring that is hidden under the air filter, crammed around the back of the bay, intertwined, etc, etc.

I don't know what to do anymore.