We purchased blazer in march of 2009 and rear a/c and heat did not work. Dealer agreed to replace free at time of purchase. Then around December 2009 we started smelling odor...smelled like propane. About three weeks later the whole truck filled with smoke and we discovered it was the rear unit. We just don't use it now at all. For some reason it has started running hot losing water through rear heater cord now....go figure!