dual climate control problem

I am getting no heat out of the passenger side of my dual climate controll in my 2000 Jeep cherokee limited. Can anyone tell me what would cause this problem?

http://www.wjjeeps.com/climate.htm

Scroll down to:
AZC self-diagnostic mode

If codes show:

http://www.wjjeeps.com/hvac_sub_assembly.htm