As I previously learned, the 94 Z28 Lt1's had an earlier and later variance within the same 1994 production year for cooling fan control. The early version has two fan relays and the late has three fan relays. The early version turns on one fan (high speed) for low, then both fans (high speed) for high. The later version turns on both fans (low speed) for low, then both fans (high speed) for high.

My question is: Does the PCM have different programming functions for early and late production 94 fan control, or, is the different way the two versions operate controlled solely by the relay and wiring setup?