Hi! Greetings from Ukrainian S12 users!
Please, don't blame me for the piracy, copyrights and other, but I've scanned the S12 manual (1986 200SX S12). 785 pages in PDF-file + big and nice pic of the electrical diagram... The engines is CA18ET and CA20E, I guess.
I have CA18ET, and the rest of the book was scanned to give to the other people. Like auto transmission - I've never heard of S12 with AT, but it's all in the manual.
So, if you need it - welcome to download, and post a topic at your forum...
http://www.yariksteel.ru/manual/s12/s12_manual.pdf - PDF Manual
http://www.yariksteel.ru/manual/s12/...%20diagram.gif - Electrical Circuit Diagram
If it will be in use to you - I will be glad to help. Regards are welcome -
[email protected] 
Best regards,
Vitalik