With the A/C problems that are showing up, I found a website with some good information for technicians that I found interesting and may help others here. Mastering Hybrid HVAC Systems, Pt 1 Mastering Hybrid HVAC Systems, Pt 2 " quote from site. The A/C amplifier uses something called Fuzzy Logic, which basically means it attempts to “think” more like a human’s mind, with more shades of grey and less black and white decisions. Included in this logic process is even an input to the A/C amplifier regarding windshield wiper status, to aid in keeping fog off the windshield. Other inputs include a grill mounted ambient temp sensor, steering wheel switch inputs, a sun load sensor, and actuator door position signals. " Even though the Prius sports an old fashioned sight glass, due to the condenser sub-cool cycle design, bubbles in the sight glass will disappear prior to the system being fully charged. This means a “add refrigerant and watch the sight glass ‘till its clear” charge method will leave the system undercharged. " Endquote. Edit ; link for prius a/c diag/repair. http://zeroreality.net/prius/repair/55%20-%20Heater%20&%20Air%20Conditioner.pdf If above link does not work go to http://zeroreality.net/prius/repair/ and then click on ------ 55 heating and A/C .
