Our 2012 Prius v is having a problem with side mirror movement (both driver and passenger) where they will each move left or up, but they will not move down nor right. Any suggestions as to what's broken? So far I have verified no fuses have blown. Have also pulled the switch out of the door and did some preliminary checks with a voltmeter and continuity tester, but with out specs on the switch or a circuit diagram, it's hard to know what I should be looking for there. Have not pulled the door panels to verify power to the mirrors themselves -- hoping I can avoid needing to go that far. --Norm
Almost has to be the switch since its the same switch operating both mirrors and your symptoms are identical for both mirrors. This system seems to be hardwired, eg no computer control, directly from the switch to the motors. I would try to get a used oem switch off ebay or price new at the dealer or aftermarket. Toyota 84872-52030 Amazon Dorman Switch Ebay Used https://ebay.to/3BO1yWW A priuschat users wiring diagram
Thank you for the diagram! I tend to agree with your assessment. The thing that was getting me, is I figured most failure modes in the switch would result in total loss of control of one or both axis (e.g. up/down, left/right, or both). Losing control of half of two axis (down and right) seems pretty weird. --Norm
But as you see, the difference between up and down, or between left and right, is a matter of applying different polarity to the same motor, and therefore there are separate switch contacts for down and for up, and for left and for right.
Indeed, this rules out the motors and the wiring, leaving only the switch which surely must be what's broken. With that, I currently have a replacement on order and will have it in hand soon. What I find weird though, without knowing the internals of the switch, I cannot find a single point of failure in the switch that would account for the symptoms. I've traced the diagram rjparker kindly provided, and it looks like the simultaneous failure of two different switch contacts would certainly do it. In my years of troubleshooting techy things, multiple simultaneous failures is unusual. It means either there's more to the switch that I don't get yet, or something else interesting is going on. After I replace the switch, I'll crack it open to see if I can tell what it was. --Norm
If one side works but not the other, swap out that switch. If the old one works on the new side you know that's not the problem...could be the sender unit on the dash or even a wire got cut or moved or crimped. I hate troubleshooting electrical problems!!
When I bought my 2010, the side mirrors were completely dead. The seller looked astonished. I bought the car anyway, opened up the switch, and went at all the contacts with GC Jiffy Bath, and it's been ok ever since. Oxidation is a process that can have its way with multiple switch contacts simultaneously, or nearly so. Full disclosure: Toyota has a TSB where they strongly discourage attempts to open or clean switches, and recommend only replacing them, for fear of fire hazard. Working on a switch as I did would be at your own risk.
