Solar Panel Roof Ventilation System

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by PriusCatMouse, Aug 22, 2021.

  1. PriusCatMouse

    PriusCatMouse Junior Member

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    I have a 2013 Prius IV with solar. I live in FL and noticed that recently this ventilation system does not come on. The vent system button located is on and have confirmed this several times. The vehicle can sit in the sun for hours and I can tell the vent system has not been on and I no longer hear or feel the vent system when I get inside after a hot day.
    If I understand correctly (I may be wrong here) the AC system and solar vent system are on the same fuse so I don’t think it is the fuse because my AC has been working normal. Any help would be great and I actually really like this feature on my car and it’s been super hot lol

    Thank you!!!
     
  2. Badchurrito

    Badchurrito New Member

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    I would do the following in order:
    1: triple check that it is properly turned on, turn it off and on again.
    If that doesn’t work
    2: check the panel to see if it’s dirty or being obstructed.
    If it’s not
    3: Run an obd2 scan or see a mechanic to have it analyzed.

    my best guess for if 1 and 2 aren’t the issue would be the solar panel isn’t indicating to the car when to properly ventilate, so maybe wiring or a sensor has gone bad? I assume the remote AC is working okay? Which would mean the solar panel is collecting power and sending it to the AC when remotely triggered, but it’s not able to send its own signal for when it wants to ventilate on its own.
     
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  3. AzusaPrius

    AzusaPrius Active Member

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  4. ChapmanF

    ChapmanF Senior Member

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    Most of the solar ventilation system doesn't rely on any fuse at all. The solar ventilation relay is an SPDT that connects the blower power input either to the 50 amp HTR fuse or to the solar circuit output. The solar connection is the relay's normal position when unpowered, so no battery power needed there.

    The solar ECU has an input from an IG-switched circuit (via the 10 amp A/C fuse)—the same circuit that flips the relay over when the car is ON—but that's only so the ECU knows when not to do solar stuff. Naturally, that circuit is off when the ECU is doing solar stuff. It gets its power from the roof panel. It has its own wired-OR connection to the blower motor's speed pulse input.

    The solar ECU does chat with the A/C amplifier; the only reason I know of is that it commands the damper servos to move to 'fresh' and 'face' about a minute after the car is shut off. Because that happens after the car is shut off, the A/C amplifier has to be getting its battery power on the unswitched circuit then, via the 10 amp ECU-B3 fuse.

    Using Techstream, you can look at the voltage the solar panel is putting out. From the 20s down to about 10, it should run the fan some (after the ten minute pause from shutting down the car); if it's below 10 volts it probably won't. You can also see the received status of the solar vent switch the IG input.

    The solar vent switch status shows up twice in the Techstream data list: once for what the solar vent ECU thinks it is, and once for what the A/C amplifier thinks it is.

    The repair manual describes a test mode you can use while IG is ON; it tests some basic functions of the solar vent ECU and the blower, and saves you twiddling your thumbs through the normal ten minute wait before venting starts.
     
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