I have a 84ElC with a newly converted AC system. (Last Summer) Air does not blow strong out the dash vents but also flows out of the floor vents. In winter I have a similiar problem with the defrost. The defrost does not want to blow fully but still get air coming out of floor vents. I was told by someone smarter than me that this could be a problem that I would have to disassemble my entire dash. Any help or advice would be greatly appreciated! Email elcamino84@earthlink.net

vacuum switch or system problem with the various doors for distribution of the air flow. May just need to adjust them. buy the service manual and follow the diagnosis.

It is deffinately a vacuum problem. All the vent doors to control where the air comes out are controlled by vaccum. Sometimes the lines get brittle and crack, or they come off behind the dash. I had the same problem, I had a loose vacuum line that connected to the back of the A/C control unit. Now I have too much cam in my car and can't produce enough vaccum to open the doors up! Good luck! -Matt

Could also be a defective actuator (vacumn servo) or even a bad vacumn switch. Check the service manual, there is a good diagnostic tree.