2005 AC

welcome!
in your first sentence, you said it was blowing with less force.

 

Your post is pretty unclear. Is it a fan problem or is it warm when it does blow?

The cabin ac blower fan lasts about 9 years. Mine ran everyday every minute the car was on for nine years.
Then one day it just stopped. Next day it came on and ran for a bit then stopped.
I replaced it with an original brand new blower. Search my old posts I did a write up on it but there's hundreds of posts on how to do it. Hard part is you have to lay on your back under the glove compartment. I think the original blower fan was $80.

If blowing warm your best bet and cheapest Play in the long run is take it to a good car ac shop. They will check the refrigerant level and if low will inject die into the system and search the system for leaks.
That's about $150 for that in my neck of the woods.
Double that if you take it to a dealer.

 

Triple that if you take it in during August.

 

There is no reason to EVER "drain and refill" a refrigeration system. For a STEALership to suggest it, could be construed as criminal as it is against the law to "top off" a system that is leaking.

 

When switching between the different air flow settings (feet, face, windscreen) do you hear motors actuating under the drive side dash?

You might also hear a light ticking sound (think portable alarm clock) or a plastic like crumpling sound coming from the same area under the steering wheel.

 

If the airflow is reduced when the blower should be blowing, there aren't many possible reasons to check out. Either the blower itself isn't performing well, or something is interfering with the airflow. The cabin air filter would be a prime suspect. After that, debris that could have been packed into the evaporator coil. (An old vehicle I had with no cabin air filter got lots of chopped-up leaves plugging the evaporator really well, but in a Prius, that shouldn't happen unless the air filter has been missing for a while or something.)

Finally, there could be a problem with the positioning of the flaps that direct airflow around inside the unit. Those are moved around by servo motors, and the motors send back position feedback to the A/C computer, so it usually knows if they are not arriving at their proper positions. It can tell you so, if you ask for the codes (hold AUTO and RECIRC while turning the car on ... easier that doing headstands in front of the seats to try to see them in action).

In a different type of failure, a linkage physically breaks, so the servo motor may think it moved to the right place, but the flap it controls did not. In a case like that, there are less likely to be codes.

-Chap

 

Could it be the blower motor resister

 

9 years is correct. My 2007 A/C blower stopped. Banging under the glove box started it again, but for shorter and shorter times. The brushes in the DC motor are obviously worn down. I bought a used blower from LKQ for $25 and a big hand mirror from Dollar Tree for $1 so I could sit comfortably in the passenger seat and replace the motor by staring into the mirror on the floor. Took me about 30 minutes, but my excuse for that is that I am 86 years old this month and not as fast as before, sort of half-fast.