when i turn my heat or air on it doesn't blow out strong on 1991 Chevrolet S10 Blazer

i put the heat or air up on high and it barely blows out the vents. i don't k now what causes this

Asked by for the 1991 Chevrolet S10 Blazer
Most lilely its either a cabin air filter issue i.e. needs to be replaced or your blower motor resistor could be faulty