Okay - so you are talking a very early Cavalier with 10 pin aldl (assembly line data link) connector.
The diagnostics equipment used on Cavaliers and almost all other pre-1997 vehicles was Tech 1.
The primary diagnostic language is KWP (key word protocol)
Tech 2 uses the later European "industry standard" 16 pin EOBD (Electronic On-Board Diagnostics) connector.
EOBD continued up until approx when emissions controls were tightened further, with the use of CAN (controller area network) protocol.
With CAN data stream technology came EOBD2, which uses the same connector as EOBD.
For those in the know, Petrol cars had to use CAN from late 2001. Diesels were from late 2004.
In approx 2010, this was replaced by MDI and so on...
Now then that's the techie bit.
As for your ABS - early ABS vehicles did not have on-board diagnostics, in the same way the very first injector engines did not.
So in summary - there is no diagnostics tester tool to disgnose the early ABS modules.
We have to go back to absolute basics.
So the checks are: -
Look for cracked or corroded toothed rings on the front outer CV joints.
Look for damaged or chafed wiring, especially in the front wheel wells.
Especially where tyre contact may have occured.
Finally look for corroded, damp, damaged or dirty connectors or their pins within the whole ABS circuit.
As for wiring diagram -
Look on page 224 of the pdf version of Haynes manual that I sent in Winter 2014.
You are looking for track lines 700 to 720.