Hi from Japan-E30 325i Conv. issue- Knowledgeble advice sought

[shopcarpro]

I have a 1987 325i conv, for the last 15 years in Japan.
Couple days ago when I trie to start the car, engine does not turn over, starter solnd does not click, dash lights do not come on. Battery voltage seems ok. wipers work, hazard works, power windows do not work. Power locks work. I am unable to locate my Haynes as I had no issues with the car ,,,,However I have a habit of disconnecting things here and there to prevent others starting my car. Sometimes the Engine ECU connector, other times main harness round connector on firewall etc. I checked all wires to ascertain that all is well. However so far as described above. Has anybody been in this situation???if so what could have been the solution.
Also wiring diagram would be appreciated on line. I believe this to be a minor issue????????? Pls advise. Thanx in advance.