99 suburban 1500 front heat out rear heat works
 

I have recently inherited a 99 suburban from my father and he had this issue before and fixed it but he is not here to tell me exactly what was fixed.
The front blower does nothing no sounds no air conditioning no heat. However the rear heat and air functions perfectly.
If I remember correctly he said the issue was located behind the glove compartment but I do not want to start tearing things apart with out some form of knowledge,
Any help out there?