I have a york gaspack (older) Model # D1GA036N08006A.

I appears the blower motor is set on the low output setting, as it only is slightly detectable at the regesters inside the house. (I have cleaned both coils and changed all return filters and still very little output on supply registers. Can the fan motor be set to medium or high output manually, by changing leads on the motor? Does the AC unit automatically monitor and make these changes? How can I increase the output to my supply side registers? Thanks for your help!!!