Even though my climate control system is not in auto mode, it still has a mind of its own. When I run my a/c, the airflow intensity level changes, and the system switches to defrost about every 5 minutes or so (even when there is absolutely no need for defrost). I continually have to set the system back to my comfort level. What causes this, and how do I fix it?
the auto mode does change fan speed. for that reason i never use auto mode and keep it in manual mode. be also advised that a lot of users hit the filtered mode switch and don't understand what it really does.
Interestingly the Prius blower motor speed control sends a pulsing signal to the motor to control the speed. Low speed: the pulse is slower frequency. The higher the motor control is set the higher signal frequency. I guess this is designed to save energy from the 12v system. Instead of using resistors to control motor speed they send a pulse. Pretty ingenious, eh? This is why I think there is something amiss in the HVAC module
This would not be a problem if I had the system in auto mode, but it happens in manual mode. As for filter mode, I don't even have that in my Prius.
Thanks Mendel! As you were posting, I simultaneously found out via google search that the button is after all, a filter mode button. Upon further digging in the owner manual, I also find the button i.d.'ed as the micro dust and pollen filter. I will try running a/c w/out the filter button depressed and see if that fixes the issue. Thanks again!
I see now that I do have a filter button, and I have certainly been depressing it. I will try running a/c w/out pressing it. Thanks!
Problem solved... I hope. The filter mode does, in fact run the fan at high speed for about three minutes. It cycles the cabin air through the charcoal impregnated cabin air filter in volume to clear the cab of micro particulates. If you are flatulent, it does wonders
