Have you checked your liftgate fuse? In my 2006 Yukon, when the liftgate fuse went out the rear ac wouldn't work nor would the electric locks for the liftgate itself.
When the front blower for heat and a/c work fine and the rear does not on the 2001 GMC Yukon it could be a blown fuse. Automobile manufacturers rarely have both of these blowers running off the same fuse.
where is blower motor resister located on 2001 GMC Yukon
The 2009 GMC Yukon has 39.0 in. of rear leg room.
The 2009 GMC Yukon has 65.2 in. of rear shoulder room.
The 2010 GMC Yukon has 60.6 in. of rear hip room.
The 2012 GMC Yukon has 39.0 in. of rear leg room.
The 2002 GMC Yukon has 39.4 in. of rear head room.
The 2005 GMC Yukon has 38.6 in. of rear leg room.
The 2005 GMC Yukon has 61.3 in. of rear hip room.
The 2008 GMC Yukon has 39.0 in. of rear leg room.
The 2014 GMC Yukon has 65.2 in. of rear shoulder room.
The 2008 GMC Yukon has 60.6 in. of rear hip room.