Accessing GM Serial Data (was: Help needed reading Ford EEC-IV...)

[Daniel R Burk]

>My 1984 Riviera has a 12-pin ALCL connector under the steering column.  I
>have a GM service manual for a 1983 Grand Prix which says the pinout of this
>connector is as follows:
>        A       Ground
>        B       Test Terminal
>        C       Air Select/Early Fuel Evaporation Solenoid
>        D       "Check Engine" Light
>        E       Unused (no wire)       
>        F       Torque Converter Clutch Solenoid
>        G-L     Unused (no wires)