300 se heater
 

I have an 89 300se. The heater works, but the fan does not blow very hard. At the low fan speed, it takes a while to get passengers warm on a cold day. The high fan button does make it blow harder than the low. Can anyone tell me what might be the problem as to why it does not blow very hard? I am used to turning the heater on after the motor warms up and the warm air getting everyone warm quickly. Am I expecting too much(is this just the nature of the beast)?