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Rear view mirror digital compass stopped working, how do I locate the fuse for it?

Discussion in 'Gen 3 Prius Technical Discussion' started by Mahmoud Bennett, Jan 3, 2019.

  1. Mahmoud Bennett

    Mahmoud Bennett New Member

    Jan 3, 2019
    Tampa, FL
    2010 Prius
    So I bought my 2010 toyota prius V about a year ago. It came with a Built-in digital compass and garage control panel on the rearview mirror. All was well until one day I noticed that the digital compass turned off and no longer showed my current direction. The garage buttons seem to work fine - whenever I click them it prompts the small red LED lights on the panel. I've clicked the power button on the mirror but the compass will simply not show. How do I got about fixing it? Plus how do I locate the fuse for the compass, it doesn't seem to appear on the manual.
  2. Elektroingenieur

    Elektroingenieur Senior Member

    Jan 8, 2017
    2016 Prius
    Three Touring
    In the Electrical Wiring Diagram (more info), the pages for “Automatic Glare-Resistant EC Mirror, Garage Door Opener and Parking Assist (Rear View Monitor) (w/o Navigation System),” in the System Circuits section, show that the Inner Rear View Mirror Assembly receives power through the DOME fuse in the Engine Room Junction Block and the ECU-IG NO.2 fuse in the Instrument Panel Junction Block.

    The Power Source section lists other systems that also receive power through the same fuses. This lets you check the fuses indirectly. For example, the DOME circuit supplies the dome light and other interior lights; if those are working, the DOME fuse is almost certainly OK.

    Similarly, the ECU-IG NO.2 circuit supplies the Power Steering ECU Assembly. If that power source were missing, the Repair Manual says the ECU would store a diagnostic trouble code and turn on the electric power steering system warning light. If that warning light just comes on briefly during the lamp test when you start the car, and then goes off, the ECU-IG NO.2 fuse is probably OK, too.

    The Repair Manual explains how to remove and install the rear view mirror assembly and the cover for its wiring. The mirror assembly is replaced as a unit; the manual doesn’t discuss any internal repairs. I’d suggest checking the DOME and ECU-IG NO. 2 supply voltages and ground at the mirror assembly connector (designed U6 or U7, depending on which version you have). If those are OK, replace the mirror assembly.

    Parts catalog reference: Figure 87-01, Mirror.