Check AC Connection - 2nd Gen 2008

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TwoPriusInTenn, Jun 1, 2025.

  1. TwoPriusInTenn

    TwoPriusInTenn Member

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    Greetings,

    Replaced the evaporator in my daughter's 2008 with smart key and back up camera. The car ran fine when I started it up yesterday, other than a leaking heater hose on the engine side of the firewall. Fixed.

    Once this was displayed, I took the dash apart looking for a loose connection, but none were seen. Any ideas? Will my Techstream help to track this down? I haven't connected it up yet. No codes.
     

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    #1 TwoPriusInTenn, Jun 1, 2025
    Last edited: Jun 1, 2025
  2. Tombukt2

    Tombukt2 Senior Member

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    You haven't connected what up you you mean hoses and refrig in ? Or things still unplugged?
     
    #2 Tombukt2, Jun 1, 2025
  3. Tombukt2

    Tombukt2 Senior Member

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    Maybe it sees no pressure yet .I'll look in manual for this character display.
     
    #3 Tombukt2, Jun 1, 2025
  4. Hayslayer

    Hayslayer Member

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    I think I've seen that previously when all the connections are not on the back of the MFD. I'm sure there could also be other causes.
     
    #4 Hayslayer, Jun 2, 2025 at 8:55 AM
  5. Tombukt2

    Tombukt2 Senior Member

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    I saw this in the generation 3 but I'm not exactly sure why. Think I had something unplugged
     
    #5 Tombukt2, Jun 2, 2025 at 9:19 AM
  6. TwoPriusInTenn

    TwoPriusInTenn Member

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    Refrigerant and heater hoses are connected in engine compartment. . Also, all connection from the wiring harness are connected inside the dash.
    Someone made a post elsewhere referring to a fuse on the driver's side, under the dash.

    Car is currently sitting with 12v and hybrid batteries unplugged. We'll see if this clears anything.
     
    #6 TwoPriusInTenn, Jun 2, 2025 at 9:48 AM
  7. Tombukt2

    Tombukt2 Senior Member

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    The under dash fuse box may have a blower heater AC fuse I'm not positive it's not hi amp of it does . There's not one hidden in the kick panel like other Toyotas. This happened just turning on ?
     
    #7 Tombukt2, Jun 2, 2025 at 11:45 AM
  8. TwoPriusInTenn

    TwoPriusInTenn Member

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    Yes. That's the ironic thing. This message just appeared. Car runs fine, just unable to access or control the AC. I'm going to check it again tonight when I get home and try to locate that fuse. Seems odd.
     
    #8 TwoPriusInTenn, Jun 2, 2025 at 2:35 PM
  9. Tombukt2

    Tombukt2 Senior Member

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    So the buttons from the steering wheel do nothing also?
     
    #9 Tombukt2, Jun 2, 2025 at 3:03 PM
  10. TwoPriusInTenn

    TwoPriusInTenn Member

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    I didn't think to check those. I will this evening.
    Thank you for helping me think through this and chase this down.
     
    #10 TwoPriusInTenn, Jun 2, 2025 at 4:05 PM
  11. saneesh8

    saneesh8 Member

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    #11 saneesh8, Jun 2, 2025 at 5:19 PM
  12. mr_guy_mann

    mr_guy_mann Senior Member

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    If techstream can connect to the HVAC ecu, report any codes. Otherwise if connections at the ecu and MFD are in fact secure, then I would suspect an internal MFD fault.

    Posted via the PriusChat mobile app.
     
    #12 mr_guy_mann, Jun 3, 2025 at 12:04 AM
  13. TwoPriusInTenn

    TwoPriusInTenn Member

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    I am finally able to get back to this. I let the car reset a couple days. HV unplugged. 12v unplugged. Reconnected both and tried the AC. The display is still unable to connect to the AC..
    AC Auto and temp control buttons on the steering wheel work. I didn't run it long. I still have to add refrigerant and compressor oil.
    Faulty display? Any suggestions?
     
    #13 TwoPriusInTenn, Jun 5, 2025 at 8:15 PM
  14. Tombukt2

    Tombukt2 Senior Member

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    So the MFD doesn't work at all in any of the button positions? Your eyebrow display with the transmission gas and speed and all of that works no problem?
     
    #14 Tombukt2, Jun 5, 2025 at 9:54 PM
  15. TwoPriusInTenn

    TwoPriusInTenn Member

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    I have attached a photo of the 4 connectors going into the back of the display from the harness. All buttons on the left of display screen: display, info, climate and audio all change when the button is pushed.

    Is anything missing?
     

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    #15 TwoPriusInTenn, Jun 7, 2025 at 1:58 PM
    Last edited: Jun 7, 2025 at 2:10 PM
  16. Tombukt2

    Tombukt2 Senior Member

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    Looks like loaded w GPS ? Looks fine I believe mine's same w these options
     
    #16 Tombukt2, Jun 7, 2025 at 2:58 PM
  17. Tombukt2

    Tombukt2 Senior Member

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    The middle wide white plug is the magic to operational MFD the other plugs I guess are the many inputs from car that middle plug is always same others might be different w varying options or such . Most MFD will power on with just that middle plug inserted for testing
     
    #17 Tombukt2, Jun 7, 2025 at 3:01 PM
  18. TwoPriusInTenn

    TwoPriusInTenn Member

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    Thank you. My guess is the MFD has gone haywire..Car runs great other than that. Did connect Techstream. No codes in AC as well! Would you concur with faulty MFD? All wire in connectors look coean and connected. Anything else I should check?
     
    #18 TwoPriusInTenn, Jun 7, 2025 at 3:13 PM
  19. Tombukt2

    Tombukt2 Senior Member

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    I wouldn't think so wen my does this and I feel not u doing the sandwich I just plug in another from any trim level plug up middle connector and unit shows display. Add two other connectors and all the stuff that MFD does it now does because it plugged up. I generally have 4 to 5 various trim MFD here
     
    #19 Tombukt2, Jun 7, 2025 at 3:58 PM
    TwoPriusInTenn likes this.
  20. TwoPriusInTenn

    TwoPriusInTenn Member

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    Thank you.
     
    #20 TwoPriusInTenn, Jun 7, 2025 at 5:29 PM
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