how do you check blend door for drivers side with dual climate control on 2003 Buick LeSabre

air conditioner works fine but drivers side blows warmer air than passenger side. I suspect the blend door.How do I get to it to check out.

Asked by for the 2003 Buick LeSabre
any good mech with a scanner can read codes and test blend doors to determine bad motor
1 more answer , 1 more comment
The lesabres are famous for this when the freon gets low. Have the a/c system checked.
Thanks so much, had system checked and sur enough - was a tad low- blowing cold now.
Again thanks , EM