check engine light on on my loyale 1992 AT sedan. Unable to locate the diagnostic port/plug. It's pre ODB2 obvioulsy, not sure where to start. thanks for suggestions!

https://www.2carpros.com/articles/subaru-diagnostic-trouble-code-definitions-1987-1994-obd1-with-code-gathering

Remove the kick panel from under the steering column.   Bolted to the column, there is a plain metal box.  there is a hole pointing toward the driver.  peeking into the hole, you can see a red LED.  [when it is blinking] 
 

Start the engine.  Look at the LED.   Long blinks are the tens place digit.  Short blinks are the one's place digit.  All numbers are 2 digits.   Codes are listed in a sequence, then repeated.  There may be only one, like 34,  or a few, 34, 31, 35.

Look up the code numbers, and or post them here.