Yaris Icon 5dr 1.33M A/C Issue

[James McGee]

Can anyone give me any information on why my car has a high pitch noise when the heating or A/C is on? The noise pitch does not change when driving.

Thanks in advance! 

[Mooly]

Hmm... does it make the noise when the heat is on and the A/C (the compressor) is off? In other words just the cabin blower operating.

All I can think of (but no one has mentioned it as far as I know) is that you are hearing what is called PWM or pulse width modulation that may be used to control the blower motor speed. Such things can be audible in what are called 'wound' components like motors and so on.

Can't really  think of much else tbh.

 

 

 

 

[CPN]

1 hour ago, James McGee said:

Can anyone give me any information on why my car has a high pitch noise when the heating or A/C is on? The noise pitch does not change when driving.

Thanks in advance! 

This may sound a strange thing to ask but is your glove box stuffed up with tissues or napkins (from drive-thrus) by any chance? This happened to me once and some of the tissues had overflowed out of the rear of the glove box and were touching the fan blades! (making a whining noise) Look behind the glove box to make sure nothing is poking out?

[flash22]

First off, check the cabin filter and make sure there is no debris in the box It's likely never been changed

£12 for the filter and a 5 min job