my 00 blazer le is fantastic in every way, ive been an auto mech 30 plus yrs and retired,my forte was suspension work and alignments then later i took raw Mack chassis and assembled complete log trucks with Serco loaders....bla bla bla. my blazer issue is twice now this winter in wisc. the heater failed me. i temp checked with infrared gun,all good..new therm, just cuz,reverse flushed just cuz. but all along knowing in my mind that prob is internal in cab i.e. control switch or stuck blend door,(sometimes noisy) my ?? is how much crap is it to find access to blend door assy and do you guys know existance of a diagram?? thanks guys. P.S. i bought 4 new Hankook Winter I-pike 409 tires, trust me when i say those things are friggin AMAZING,blazer goes in 2x4 where my Dakota cant in 4x4....ya ya i know its cuz its a chevy.(im a chevy guy) just bought Dodge cuz i needed something to work on lol. thanks guys