1994 Mazda B3000 Check engine light comes on - failed emiss

Hey guys:

The check engine light was staying on in my 1994 Mazda B3000 (3.0 V6) and it failed on the HC and NOx portion of the emissions.

Niether I nor an auto parts guy are able to find a module for connecting a diagnostic tool to get the codes. I have been scouring the internet but I cannot find a way to get the "blink codes" from the dash panel. Would anyone happen to know how to do this?

FYI: I replaced both O2 sensors, the egr valve, the pcv valve, a bad vaccum line that goes from the PCV to the charcoal canister, changed the oil and filter. The truck failed a second time with slightly higher numbers. I wonder if I got the left side and right side O2 sensors mixed up. The part description did not specify which was which. Maybe the valve seats are worn?