Is it possible for heating to fail running stage one, but eventually fire up stage two?

2-stage Gas HVAC (AS VS90) seems to only blow cold air after stage one heating is called at the thermostat, but the system eventually starts heating effectively under the stage two call.

My theory is that the W1 may not be connected at either the thermostat or heater end, or the wire severed/burned in between.

Would a missing W1 connection do this? Or to ask the real question on my mind: Does heating REQUIRE W1+W2+G for the second stage to run, or would W2+G be enough to allow stage 2 to proceed even though stage 1 was never tripped?

submitted by /u/indgosky
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