Heater blower motor power

I have a 91 euro 3.1 and my heater/AC fan seems weak. You can feel the air comming out when it is at full blast but it is not pushing that much air. This is kind of annoying when it's only -20C outside and you need to where a toque and winter jacket inside the car (altough I have a winter thermostat in my car now so we'll see how bad it is next winter). Is the weak fan normal?

Also,I was wondering if anyone knows of places on the internet where you can find technical information on Lumina's?

Thanks in advance!!

www.helminc.com for factory gm shop manuals. I would try cleaning out your heater ducts. The area underneath the windshield under that plastic mesh. Leaves, dirt and other particles build up and clog up the heater core and evaporator for the AC. Last, make sure your fan is simply not going out, or if your Fan Resistor clustor just next to the fan is not causing bad connections. Your fan may be broken also.