92 fld120 with N14. How do I connect an eld?

That’s the plug I’m talking about
You can plug the e log into that…. I think…I know it works for a diagnostic computer. Not trying to hurt anyones feelings but the red top is probably the most meaningless measure of an engine ever because they’re completely independent from anything that matters. I actually always switch the tops on ones I rebuild because the stamped steel covers like to leak.

 

I think that early would be OBDII inside and 6 pin under the hood. Could be behind the plastic panel on the left of the clutch pedal, or over the steel panel over the clutch pedal

 

I may be wrong but I don’t believe obd11 was on the commercial truck market until long after these trucks. I know for certain an 01 fld120 with an n14 has the round plug

 

Most trucks had OBD connectors (IIRC), until 93 or 94, when you startd to see the round 6 pin.