OEM 3 way coolant valve 16670-21010?

Experience has shown that the Toyota part is the most reliable. Just get it from a reputable source (like a dealer or rockauto, not ebay or amazon)

Posted via the PriusChat mobile app.

 

There is nothing to break in a three-way valve for a thermos system. The cause of all the troubles is the wear of the tracks in the potentiometer, which transmits its data to the ECM when the valve is turned to a certain angle.
RVQ121 12V 502 5K Ceramic potentiometer strip PPS-GF40 360 rpm
If you can find such a potentiometer and replace it, your three-way valve will last longer than the car.
The potentiometer costs about $7-$8

 

Of course, the three-way valve must be removed to gain access to the potentiometer.
The potentiometer is located under a cover that is secured with 5 screws.
View of the potentiometer with the cover removed.

 

Everything should work correctly.
In case you need to calibrate, you can use the manual (page 4), there are voltage values in three positions.
https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/2054m/cip1121a.pdf

 

Hmmmmmm so I could make this switchable by switch or such interesting . I have one open already which looks very nice inside don't seem stuck or fouled .

 

Mechanical jamming is unlikely unless a piece of rubber hose gets into the tap. The three-way tap drive motor works very rarely, the operation lasts for a minute, and therefore, by replacing the potentiometer, you will breathe new life into the old three-way tap.