I have a f350 99psb, i put a new blower, compressor, dryer, and orfice tube, i also put the heater bypass valve. The problem is it doesn't blow enough air from the vents. I put i on max and a vent opens in the bottom and i can see the blower from there. I just don't know why its not blowing faster air. i also took all the vents off and put a leaf blower to make sure there was no plastic bag stuck in the vents. Thanks.

 

have you checked your blower motor resistor. Does it blow at all on all the speeds?

 

This is going to sound silly, but it has happened several time over the last few years. Check the return vent near the floor for a Walmart, foodlion, or whatever bag. There have been several sucked up, not to be seen again. I'm not sure if you could see it unless you look for it. I think the last was removed using a piece of coat hanger with a hook on the end.

 

It blows all speeds but very little air comes out, on high you can hear the blower air comes out but not very fast, if i close one vent it helps the others a little, where is the motor resistor located at? thanks for the help

 

Ill check again it's happend to me before thanks

 

If you turn on the heater,does the airflow change?

 

The blower motor resistor is on the cover over the coils under the hood it is right behind your a/c accumulator should have a plug with 4 or 5 wires going to it. I just replaced my blower motor this past weekend because it was beginning to blow slower. If you hook a meter up to the plug that goes to the motor you should get 13v +/- (with truck running) and the fan on high. If the voltage at the motor is ok and you still arent getting the airflow i would bet on a bag being sucked up or a blower motor going out.