i have a 1989 mustang gt and i was wondering if anyone knows where the self diagnostic port/connection is on the vehicle.usually they are located on the driver side under the dash but i don't see it there on my car

 

putting the diag port under the drives side dash was part of the OBDII standards that became mandatory in 96.

yours will be in the drivers side fender well under the hood. between the innter fender well and the brake booster/master cylinder. there should be a protective cap on the end. if not, good luck.

autozone and other parts store sell a code reader for ford EEC systems.