I've got a 96 Z71 pickup with the 5.7 and 4X4. The I'm trying to pull codes from the ECM using the jumper wire to short the A port to the B port on the ALCL plug. I have located a plug under the drivers side dash. Is this my ALCL? Also, how are the plugs pinned out? I have the 2 plugs to the farthest right , top and bottom jumped together and I can not get my check engine light to blink. I know the plug is ported A thru M and skipping I. Which two ports are A and B?
http://obddiagnostics.com for a free software download that will allow you to use a laptop to interface with your vehicle. Only downside, you do need to buy an interface, unless you are capable of building one. -Chris