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?

95 and newer require a code reader. go to autozone for a free scan and good starting point

You've got the OBD2.. a little more advanced than the old "jumper wire" diagnostics..

You can buy an obd2 scanner, here they are about $180cdn.. Or You can take it to a shop like 4freddie mentioned, but here they charge you to scan it

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

I am looking to buy a K3500.

I have the code reader but where is the port in order to pull the codes?

Thanks

Under the drivers side dash. Usually located nearly underneath the column. 16 pin connector. You really can't miss it.