My inverter over heated. Looked at reservor for motion of water saw none. Took car to toyota for pump recall.When I got it back I heard the pump. Never heard it before. I don't think it ever worked. & water is flowing in reservor now. Now I am thinking about the HV bat. fan because I never never ever heard it working. When does it come on and how could I test it?
I think many people never hear their battery fan come on, although it does run at a very quiet slow speed often enough. It will only run on high under real heat stress. If you drive mainly on the highway, use the A/C, and do not encounter much in the way of big hills, then it will go unnoticed. If, after years, you do hear it, it means battery trouble is brewing, due to the internal resistance of the cells rising, or due to the fan being clogged with dust, hair, etc.
I put a piece of filter material (intended for vacuum cleaner motor filter) in the fan inlet on our 3rd gen, soon after purchase, about 18 months back. FWIW, I've never heard our fan, but periodic checking of that filter shows it's picked up a few things, a bug or two and some lint. So I'd assume the fan's running, just not audible.
Any time you get a nice hot summer day and a reasonably long drive, at the end of your trip I guaranty it will be running. Leave the Prius in ready and (with all other fans off, engine off, radio off etc) get out of the car and walk around to the right back door. Place your ear right next to the vent and you'll hear it running. It's whisper quiet on low speed, you really need your ear right there at the vent to hear it.
Thanks It is always hot now in jersey. I will take a ride and check the fan. I am going to clean the fan in the next few days. I heard it can be very dirty after 7 years.
I found my way into the fan. not easy. very hot day too. only found dust on the blades. vaccumed it out. I hope it works, because the dreaded triangle came on & car quit on the highway on a 104 degree day. I still hope the inverter water pump was the problem.
That's easy enough to check. Have you had a look to see if the inverter coolant is circulating in the reservoir yet?
It's worth a look because it's apparently common not to get all the air out of the coolant loop after replacing the pump. A week after mine was replaced the same warnings re-appeared; the cause was just trapped air. In eight years in Dallas I've never noticed the battery fan running, so don't panic about never having heard it.
