I have an 85 Monte w/4.3 motor. I'm trying to diag a check engine light, but my reader won't recognize the car's computer. All of the wires of the OBD plug are installed along the top row, and not interspersed throughout both rows. Is that normal? Does someone out there have a color coded wiring diagram for this OBD1 connector so I can check to see if the pin outs are correct?
Thanks

 

This is a good link to bookmark for future reference:

How to read older GM OBD diagnostic codes for free

 

U can always use a jumper wire and count how many times the check engine light flashes it a easy cheap way to do it but have a pen and paper to write with