Hi all! Recently I bought myself a cheap, high mileage Prius II 2005 and I absolutely fell in love with it. I do all the maintenance myself and since the car came with no history I already among others did; oil and filter, replaced coolant, gearbox oil change, spark plugs, air filters, ‘new’ drivers seat, all brakes. The Prius drives great now and sometimes even manages to get 3.9l/100km (60MPG)!! Anyway, there is one thing left that is keeping me up at night, the AC. I went to a local shop to get the refrigerant vacuumed out and replaced (with the correct refrigerant and oil!), since the AC was not working great. After that, the AC still doesn’t work as it should. When the car is stationary, the AC just blows warm/outside temp air. I can hear the compressor kicking in and it sounds to my untrained ear, healthy. When I start driving and coming up to speed (minimum ~50 kmph/31mph) I can start to feel cold air, which will become colder when I drive faster. I connected my laptop with Toyota Techstream to the car. When I do tests on the compressor speeds, the compressor gets to the selected speed (RPM) no problem. When I check the data, I can see the evaporator temp come down from 30 degrees celsius (86F) to around 10 degrees (50F) when I’m driving. Coming to a stop it climbs fast to 30 degrees again. There are no error codes. Since the AC cools when there is enough air going through the condensor, I suspect that the ECU is not sending the signal to the fans to spin at high speed, but I’m a bit at a loss as to where to go from here. The fans spin, but not fast. The direction is correct, tested it with a sheet of paper and it gets sucked towards the car/engine. Any help would be greatly appreciated, especially since we're going on holiday next week to Italy. PS, today when getting in the car and stationary, the AC blew cold air for the first few minutes (5 degrees C (41F) evaporator temp) before getting hot again...
Small update. Checked both fan relais with my multimeter and they check out fine. Drove on the freeway today for around 20 minutes and the AC was supercool. After getting of the freeway, the temperature climbed a bit, but still ok. When getting to a stop the temperatures unfortunately climbed again. So to me this really sounds like an airflow/fan issue. Anybody has some suggestions?
What does the condenser look like - what is the condition of the fins? If the fins are corroded and crumbling (or clogged with dirt or debris), that will reduce the ability to dump heat. Try spraying water on the condenser when it is blowing warm air, see if that helps. The radiator fans turn on LOW with A/C function. The fans turn on HIGH only when the ECM senses high engine temperature. Posted via the PriusChat mobile app.
