01 T&C A/C working in back but not in front
 

My mother has a 2001 Town and Country 3.3L Engine. The A/C in the front of her van is not working. The blower is still blowing but the air is hot. The A/C in the back of the van is working just fine. Does anyone know where I should start in trying to fix it.

check freon level

Took it to Pep Boys and the freon level is fine. They can't even figure out what is wrong with it.

any competent AC tech can figure it out take it else where.