I have a 1993 90CS.
On heat, the blower motor has great air velocity from the vents.
When I switch it to air conditioning, I can't tell if the motor is operating! I can feel cold air when I put my hand to the vent, but there is no velocity to the air.

With the heater operating fine, I am not sure if it is the blower motor. Maybe a flap preventing the cold air or something?

Any help is appreciated.

 

is it an automatic climate control? if so then the fan speed is controlled automaticly ... but if you set it all the way to low it shoud go full blast ... and also if its an auto climate you can do diagnostics on the head unit i belive the bently manual tells you how to do that ... don't know if it's going to help though..