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ToyotaTom, Toyota Technician
Category: Toyota
Satisfied Customers: 1416
Experience:  Toyota, ASE, MSE, MECP Certified
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2001 Prius: above/behind the steering wheel there is an intermittent

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2001 Prius: above/behind the steering wheel there is an intermittent sound -like an electric type-writer. It makes a series of clicking sounds- like sending Morse code. No noticeable driving problems.

ToyotaTom : Hello, and thank you for choosing Just Answer to help you with your questions!
ToyotaTom : Obviously without being there to see it and hear personally to try and find the root source of the noise it is impossible to tell you what it is via Internet
ToyotaTom : However
ToyotaTom : By your description I would have to say that it sounds like an ac servo in the air conditioning box. These servos are basically little motors that control the hot/cold mix, or the selection from vent to defrost to floor etc mix
ToyotaTom : These motors control little doors that move and change the airflow
ToyotaTom : When these start to go badminton they can start to make a kind of erratic clicking noise
ToyotaTom : They can make noise for months or even years before actually failing completely. For the time being I wouldn't worry about it too much. The servos are usually in the ballpark of around $125 each, but labor can be quite costly to replace. Usually several hundred dollars.
ToyotaTom : Obviously, for an accurate diagnosis, yu would need to see a dealer and pay usualy an hour diag fee, which is arund a hundred bucks. But if it were my car, I wouldn't worry too much about it until you have something showing major symptoms or malfunction
ToyotaTom : I hope this helps, but if I can help any further by clarifying anythin, please let me know.

Thanks. That makes sense. Would the AC servo continue to function when the AC is turned off? I tend to use the defrost when it is raining and it is usually cool air even if the AC is not on.

ToyotaTom : Sometimes yes, sometimes it will stop between 30 seconds to a minute after you shut it off. Depends on which servo it is
ToyotaTom : Sometimes it will just stop after you shut off the ac. Sometimes it won't, and will keep hunting for "home" clicking all the time

'which servo'.... does this mean there is more than one?

ToyotaTom : Depending on the trim level of the car there could be a few
ToyotaTom : All should have one for blend door, which is the hot/cold mix
ToyotaTom : All should have the one for mode door, which is defrost, bent, floor mix
ToyotaTom : Some have an additional one for passenger side blend (hot/cold mix) for dual zone ac
ToyotaTom : And should also have one for the recirculation
ToyotaTom : If coming from the drivers side, will usually be either the blend door or mode door
ToyotaTom : The recirculation door or passenger blend motor would be from the passenger side ofthendash

OK, I understand how each of the vents would have a door with a switch to change positions, and a motor to operate the switches...


This helps greatly and I will live with the sound for a while. I may play around to see if changing AC settings makes any difference. Thank you very much.

ToyotaTom : Very welcome. Have a great night! And I wish you the best of luck!
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