My 86 makes a buzzing sound when the LH door is opened with the key in the ignition - it also buzzes briefly if the seat-belt isn't buckled.
The wiring diagrams for 1985 show that the convenience center had a buzzer for those two alarms. It may be the case that it has simply been pulled from the board. Here is where it should be:
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It is GM part 14036201. OEM/NOS is expensive as hell:
1982 – 1992 GM Ignition Lock and Seat Belt Warning Buzzer NOS # 14036201
$95.00
http://www.oldsobsolete.com/product...ck-and-seat-belt-warning-buzzer-nos-14036201/
You could always make your own. Any buzzer or chime wired to a battery lead (e.g. the orange on 140) and out on the 80 pin will work - provided the light green wire to the column, the switch in the column, the tan wire from the key switch to the door jamb switch (and the jamb switch itself) are good.
There should be two ground leads connected to the driver's side door jamb switch. A white one for dome/courtesy lighting and the tan for "key in the ignition".
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