Wiring colors and location

Discussion in 'Gen 3 Prius Audio and Electronics' started by AzusaPrius, Jul 18, 2020.

  1. AzusaPrius

    AzusaPrius Active Member

    Joined:
    May 27, 2020
    675
    326
    0
    Location:
    Apple Valley
    Vehicle:
    2010 Prius
    Model:
    IV
    Just wanted to put this up as it may help out those who like to install their own audio system or alarm system. Screenshot_2020-07-18-16-18-23.jpeg Screenshot_2020-07-18-16-18-33.jpeg
     
    kenoarto and Terrell like this.
  2. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    Thanks. I am looking to install a tilt sensor (against catalytic converter thieves) and a proximity sensor (against bears, for when I go camping). Just got a Viper 3105V and am reading up on the install. I won't be installing all the other features, since I don't think I really need them.
     
  3. AzusaPrius

    AzusaPrius Active Member

    Joined:
    May 27, 2020
    675
    326
    0
    Location:
    Apple Valley
    Vehicle:
    2010 Prius
    Model:
    IV
  4. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    The key fob has a panic button. Is there a location inside the car which can also trigger the panic alarm? For example, what about a tilt sensor that triggered the car's panic alarm?
    My understanding is that the Gen 2 Prius came with the alarm system already built in (but not activated), but that the Gen 3 did not?
    I've not played around with the car's panic alarm. Does the door trigger set it it off if the car is locked?
     
  5. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    Thanks for the chart. But now I have some questions, and hope you can help me. Forgive my ignorance, I'm new to this stuff.

    Your chart says, "12 Volt constant" for "Dash fuse box ... pin 1"
    How do I tap into that? I see the large white wire but it goes behind the dash fuse box.
    In checking the fuses with my meter, I see that fuses for CIG and PWR OUTLET are powered only when the car is on (I assume they are the aux ports in the middle console box and in the middle under the shifter.)

    There is a row of empty fuses which are not marked which are always powered. And idea what they are used for?

    May I tap into one of these for the 12 Volt Constant? And if yes, what is the correct way of doing it? Any wire coming off that would prevent the cover from closing...

    Or how about using the spot labeled RR FOG (which says "No circuit" in the Owner's Manual -- I assume this is for the nonexistent rear fog lights? I didn't check for power there.)

    Fuses.jpg
     
    #5 Terrell, Feb 26, 2021
    Last edited: Feb 26, 2021
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    When you look in the Electrical Wiring Diagram (more info) at the Instrument Panel Junction Block, you can see the view from below (showing the fuses), and the view of the side facing the driver seat (this one, showing connectors 2C, 2D, and 2E), and the side facing the firewall, where the similar connectors 2A and 2B are.

    ijbA.png

    2E is the fat wire bringing the juice in from the underhood fuse box. You don't really want to do anything directly with that ... there's a 125 amp "DC/DC" fuse in the underhood box, but this wire originates on the converter side of that. This is just bringing power in to this junction box, which contains not only fuses but also a bunch of relays controlled by the Body ECU, divvying up the power to the various terminals of 2A, 2B, 2C, and 2D going off to all their appointed places in the car.

    If you then turn to the Instrument Panel Junction Block "inner circuit", you see several pages in this vein:

    ijbIn.png

    This, of course, is schematic, not necessarily shaped anything like the real innards, but straightened out for ease of reading. The three leftmost vertical rails coming down from the top here are all derived straight from 2E, the input, so they are always supplied.

    You can see there's a spare fuse position derived from the IG1 no. 3 relay (so it would only have power with IG on) and coming out on connector 2A position 15. Then you can see several spare fuse positions that are always powered. One of them comes out only on 2A position 12. One of them feeds 2B position 24 and 2D position 15. And so on.

    If you look at those positions on the 2A/2B/2C/2D connectors (maybe preferably on 2C or 2D as they are so much easier to reach) and you find them open, with no existing wire coming out, then you're free to pick one of those positions and add a terminal of your own there. That's how you avoid the fuse-tap wire getting in the way of putting the cover back on. Skip the fuse tap, just pick one of the unused fuse positions, put a regular fuse there, add your new terminal to the corresponding position of one of the harness connectors coming off the side, and you're all set.

    Interestingly, because the diagram is schematic, and the spare fuse spots are unlabeled, it looks like you'll have to use a meter to find out which physical fuse slot comes out on whichever 2C or 2D terminal position you pick. But that should be straightforward.

    The EWD will also show you what terminals are used in those harness connectors. I have that info saved for the 2C connector (from when I added fogs; the built-in fog fuse comes out on 2C position 8). You can see the 2C connector includes terminals of two different sizes. The larger ones are the 1.5 mm blade, 82998-24350 female. The smaller ones are the 0.64 mm style II female, 82998-24290.

    The construction of those large harness connectors is sort of interesting. They separate into three 'decks'. When the decks are stacked together, they have bits that poke into each other and act as secondary terminal retainers, keeping each others' terminals from pushing out. So to add a new terminal at an unused position, you unplug the connector, separate its decks, click the new terminal into the right hole, then join the decks back together and plug it back in.

    (Edit: come to think of it, I don't remember for sure whether 2C came apart in decks like that. I looked back over my auto headlights post and realized when I described the 'decked' construction there, I was talking about L7, one of the plugs to the Body ECU.)
     
    #6 ChapmanF, Feb 26, 2021
    Last edited: Feb 26, 2021
  7. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    Thanks! Now the real trick is getting at them. Just looking at the fuse box, I need to be a contortion artist. :) Is there an easy way of getting at the wires? Or do I need to remove things?
     
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I didn't find adding the fogs very difficult; again, that meant adding a terminal to connector 2C. That one's right on the side facing the driver's seat. Pop off that "lower instrument panel finish panel" and you're looking pretty much right at it.

    Now if you picked a terminal position in 2A or 2B, that, I imagine, would be a job.
     
  9. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    I can't figure out how to easily remove the lower instrument panel finish panel. It looks like there are some metal clips holding it in?? I know some panels are hard to pull out without removing others.

    And how do I bring the positive wire from the siren from under the hood in through the firewall? Have others found an unused wire to piggyback on? Or do you drill a hole through the firewall?

    I am almost ready to throw in the towel and have it "professionally" installed. I've read that Best Buy is a good place to have it done, but I've also read that they use T-tap wiring connectors which I'd like to avoid, since they can "bite" into the wire, causing poor connections down the road. I prefer solder.
     
    #9 Terrell, Feb 27, 2021
    Last edited: Feb 27, 2021
  10. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    If I remember right, your journey to the lower IP finish panel begins with the plastic over the driver's door sill, which just pulls up. That frees the corner of the corner kick panel (there is also a plastic nutlike thing on that, up by the firewall, spins off but can just be pushed back on). With that kick panel out you reveal one screw that secures the lower IP finish panel; with that screw removed the panel just comes toward you, pulling out several clips.

    Where the engine room main harness goes through the firewall, it goes through a rubber grommet. The grommet has an extra nipple that you can pierce (am I allowed to write that on PriusChat?) and sneak an extra wire through. I did that for the fogs. I wonder if I will be able to squeeze an additional wire through beside it. I may one day find out.

    I agree with distaste for insulation-displacement connectors. Solder is great in assemblies, circuit boards, things that don't move, but wicks up strands of flexible wire and is avoided there by auto/air/marine builders for vibration reasons. Toyota would like you to use nice parallel-splice crimp sleeves.
     
  11. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    Thank you! Looking at the main wire harness coming through the firewall on the passenger side, there appear to be two small indentations. I thought these might possibly go through, and tried a very small wire. But then concluded that these might possibly be small screws, to hold everything snug. But I'll have another look, and maybe try poking with a more sturdy wire to see what happens.
     
  12. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    How did you get your wire through for your fogs? Is there a special tool to help feed a wire through the nipple? The wiring harness is so far back into the corner that it seems almost impossible to reach it. I was able to carefully poke a wire through from the passenger side, but trying to grasp it from the engine side I just was not able to get my hand in there. I'm tempted to just drill a hole through but realize that then I'd have issues insulating it from shorting as well as water.

    Then I started wondering whether there might be an unused wire from the engine compartment fusebox to the inside. There are at least two unused spots, one is fuse 4 labeled S-HORN, another is fuse 14 labeled MAYDAY. (Bothe those names sound like warnings!)
     
  13. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Did you remove the windshield wipers and cowl?

    If not, you'll need to get help from a friend with three elbows.
     
  14. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    So THAT's how you get to the cable grommet nipples? I've been crawling underneath the console after removing the lower tray. Hmm, I'll have a look at it. But that sounds like something I might not be up to doing...
     
  15. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Wipers out, cowl out, is just the same routine you need to learn to get to the spark plugs or the brake stroke simulator bleed screw, so it becomes second nature after a while. You'd be surprised how much more you can see and reach with them out.
     
  16. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    GOT THE WIRE THROUGH THE FIREWALL AT LAST! And I didn't need to remove the wipers or cowl. :)

    I spent hours just pondering how to do this, thinking about what tool(s) might be used to get through the firewall grommet and snag a wire to pull it back through. I even woke up at night pondering this! I read many things online, and watched many YouTube videos. What helped most were comments here on PriusChat from ChapmanF about the nipple, and the instructions in Step 6 of the file "PriusChat_Fog_Lamp_Install_Prius_Color.pdf" somewhere here on PriusChat.

    I looked carefully and probed the firewall grommet on the driver side, but that seemed hard to get to from the engine side, and I didn't like the idea of making a "hook" to drag a wire back through, for fear it would be so big it might cause trouble.

    So I tried the passenger side. At first, I tried pushing a straight wire through the firewall grommet on the passenger side from the inside of the car, but was afraid of damaging wires in the wiring harness, which bends right about where the "poking wire" comes out in the engine compartment. The poking wire did break through the grommet a little bit, too close to the harness, only enough for me to see the very tip, and not enough to get a hold of, let alone to snag a wire to drag back through. Plus, it's very hard to get my hand in there!

    Jamming my hand in and blindly following the wiring harness, I was able to feel the nipple. From inside the car, I tried using a very long drill bit, turning it by hand to pierce the end of the nipple, but the nipple is very strong and stretches. So that didn't work. Then I thought that if I might somehow get a razor blade in there, I might be able to cut off the tip. But the nipple is very close to the wiring bundle, and my hand barely fit, so thought I might accidentally cut into the harness. I also thought about using sharp scissors or an exacto knife, but the space is so small I couldn't figure out how to hold the nipple and cut it.

    (That's why ChapmanF suggested removing the wipers and cowl - because the space there is very limited!)

    The breakthrough (pun intended) came when I realized there are two nipples, one near the top and one near the bottom of the grommet. The lower one is not as close to the wire harness where it bends, so more out of harm's way. By holding a very small pair of sharp blunt-tipped scissors (made for cutting nose hairs!), I managed to cut about half way through the nipple (cutting blind, I must say). I then tried to feed a wire from the inside of the car though, but the remaining part of the nipple prevented this, so I tried -- hope against hope -- to feed a wire through from the engine side, and it easily slipped through! I then grabbed it on the inside with a long flexible grabber tool.

    Next I'll try to tape that nipple closed over the wire and add some wire conduit. Squeezing my phone in there helped me to see what I had actually cut and how it needs to be taped up (I see it's closer to the firewall and not very much at the tip). A phone camera is a very helpful tool for seeing things in tight spaces!

    Thanks for your help and encouragement, all!

    Here are some pictures:

    NippleCut.jpg GrabberToolPull.jpg
     

    Attached Files:

    #16 Terrell, Mar 4, 2021
    Last edited: Mar 5, 2021
  17. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Cowl out takes minutes. Anyway, somebody needs to scoop out the leaves every now and then. :)

    I might break out the PlastiDip for that rather than tape. Somebody without a can of PlastiDip handy but with a tube of some silicone goo might use that instead. PlastiDip is soluble in petro products so maybe silicone is more robust underhood, but I've had fine results an a location like that where no petro liquids are hitting it.
     
    #17 ChapmanF, Mar 5, 2021
    Last edited: Mar 5, 2021
  18. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    I believe you -- but for someone who has never done it, it would take me a very long time to figure everything out.
     
  19. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    11,766
    8,508
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    For those who are philosophically opposed to repair manuals, I think there are metric scads of online pictorials and videos about it, since it is such a common operation, needed for the simplest things like spark plug changes.
     
  20. Terrell

    Terrell Member

    Joined:
    Feb 10, 2010
    235
    99
    3
    Location:
    Wisconsin
    Vehicle:
    2010 Prius
    Model:
    II
    I'm not opposed to repair manuals, just opposed to spending a lot of money on them. :) I do look at videos and whatever I can find online. And find great help here on PriusChat. When I was young, I did a lot of car maintenance myself, even rebuilt my Triumph Herald 1200 engine with the help of a friend. Cars have changed a lot and gotten much more complex since then, and I have gotten older and less flexible since then as well! Add essential tremor to that and some things get much harder. But as my mother used to say, "There's only one alternative to getting old." And now during COVID, I don't have "three elbows" (message #13) of a friend to lend a hand. I'm thankful for what I can do. And thankful for the help I find here. :)
     
Loading...