Underdash connector in 81? What is this?

[JavierB]

Hi everyone again.

Under the dash of my 81 on the left, in front of the fuse panel, is a 5 wire connector just sitting there.   It says something like "PED PACK CON II " on it, but I think thats just the name of the electrical connector.  It is screwed in place, not just dangling, so seems like a factory connection.  What is it?  Is it for the 305's engine computer?  Is it a diagnostic output?  Images below.

[JavierB]

Okay, so I guess this is a first generation diagnostic connection with only 5 pins.  I was a bit confused because I've only seen 12-pin connectors for diagnostic readers, but hopefully there is a cable that lets this work in a reader.  Thanks for the help folks.

 

[IndyJimW]

Test lead for 1981 Chevrolet.

Diagnostic Connector (Test Lead Is At Terminal D)

 Used at the assembly plant to verify proper system operation--prior to shipping the vehicle--the trouble code test lead is located in a connector under the dash.

KEY OFF
    Grounding the test lead with the ignition OFF will cause the ECM to display any stored trouble codes.

KEY ON/ENGINE OFF
    If the test lead is grounded with the ignition ON and the engine OFF, the ECM will flash a code 12, send a 30 dwell signal to the mixture control solenoid, energize all ECM controlled solenoids and pulse the idle speed control motor in and out.

ENGINE RUNNING
    If the test lead is grounded with the engine running, the ECM will function normally except the system will go to closed loop immediately if the engine is warm and the oxygen sensor is hot.

 

Good luck all,

Jim Wood

 

Edited August 3, 2021 by IndyJimW