HVAC Recalibration

I recently had my 2013 Avalanche not start on me.  
As I clearly had no power I checked the battery
terminals and found that the negative was loose,
probably not tightened during the recent pre-
purchase inspection.  I tightened down the terminal
but found that all of the measurement features went
metric.  I presume that this was the factory settings
as the truck was originally from the Canadian
market.  Changing back to the English system was
simple but from that point on my air conditioning
has been inoperative.  Reading online I found that
this is a common problem for GM vehicles when the
battery is disconnected and requires that the HVAC
system be recalibrated.  I have followed the
instructions several times but have not been able to
resolve the issue.  In the recalibration steps it says
to pull the HVAV/ECAS fuse.  I have tried pulling
fuse number 55 repeatedly as part of this process
but have had no success.  Am I pulling the wrong
fuse?  If so which fuse should I be pulling for my
particular vehicle?  Could there be a fault code that
I don't know about that is keeping the recalibration
steps from being successful?