So, in an '01,,,, the First thing would be which "01" do you have? (during the run, there was an extensive, electrical, change and you may not even have a GEM)
All you have to do to determine if it's like a 2000 or a 2002 is to look at the Instrument Cluster. If you have a Trans Temp Gauge and a Digital OD in the cluster than you treat your truck like an '02 (which had the GEM replaced by a "Smart Cluster" that actually became a Module). If not then you Do have a GEM and should always treat your truck (electrically speaking) as a 2000.
All you have to do to determine if it's like a 2000 or a 2002 is to look at the Instrument Cluster. If you have a Trans Temp Gauge and a Digital OD in the cluster than you treat your truck like an '02 (which had the GEM replaced by a "Smart Cluster" that actually became a Module). If not then you Do have a GEM and should always treat your truck (electrically speaking) as a 2000.