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Add heated seats

Discussion in 'Gen 2 Prius Accessories & Modifications' started by R-P, Nov 15, 2017.

  1. R-P

    R-P Active Member

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    We have a Volvo with heated seats and it's really nice for your back after a long day.
    Especially the back side (more so than the butt-part). Unfortunately it is not separately switchable, but that's a minor detail.

    I think I read about someone fitting this to his Prius afterwards, but I cannot find the thread.
    Is it possible? And if so, could you just hook up the back-side? Or is it series wired like the Volvo and driven by a PWM signal programmed into the ECU? (I think that is how it works there, the dealer can set/alter the low and high setting).
     
  2. DonDNH

    DonDNH Senior Member

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    I got an email today from my local Toyota dealer with an offer to have heated seats installed. You might check if a local dealer will do the same for you.
     
  3. valde3

    valde3 Senior Member

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    Here all the Priuses came (and still come) with seat heaters. Gen 2 seat heaters are just controlled from switches installed in the panel below dash https://image.nettiauto.com/extra/carimg/00/08/82/02/88/8820288_l_80612255.jpg

    But if your just going to install a aftermarket seat heater you can install it the way you want. So if you wanted you could have separate controllers for seat bottom and back or anything else you wanted.
     
    #3 valde3, Nov 15, 2017
    Last edited: Nov 15, 2017
  4. R-P

    R-P Active Member

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    Cool to see those buttons. I always wondered what I could do with that large piece of plastic (and how much room is behind it... well enough for mounting switches...)

    I have add-on cheapo heaters that you attach with elastic band, but they are cumbersome. It was only after I fixed a break in the Volvo wiring that I even contemplated adding it to the Prius. Just get some seats on a Finnish junkyard and swap some parts over... :)

    I could ask the dealer, but I doubt I am willing to pay what he asks, being a Dutch cheapskate and all...

    Thanks for the tips!
     
  5. valde3

    valde3 Senior Member

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    I checked and only junkyard that had seats for gen 2 Prius wanted 200e just for a (pretty bad looking) driver’s seat. Junkyards are expensive here. I’d really love to go to US junkyard.

    It’s not really hard to take seat partially apart and insert seat heaters. I haven’t done it for a Prius but it looks just like most of seats. Here’s a Toyota manual on how to take the front seat apart https://attachments.priuschat.com/attachment-files/2017/09/131813_72_-_Seat.pdf

    If you decide to go for aftermarket heaters maybe this picture of 2004 Prius seat heater taken with heat camera might help you get the correct sized elements: seat
     
    #5 valde3, Nov 16, 2017
    Last edited: Nov 16, 2017
  6. R-P

    R-P Active Member

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    Thanks. If going through the trouble of not just swapping them from a junkyardseat to mine, but making it myself or getting ready-made-pads, a whole new option opens up: like adding rear seat heating too :) The kids will love me for it...

    In the Volvo, it was quite hard to open up the seats because it was all closed with only-use-once metal rings (with syringe-sharp ends) you had to bend open and reuse.
    And the wiring was routed through indentations in the foam. I made a rudimetary foamcutter last year for styrofoam, maybe I could use it for the foam on the seats too.

    I looked for a Volvo junkyard after smashing into a guard rail with my parents Vovo IN SWEDEN. I could not find a single one (pre-internet...).
    Not saying Finland is like Sweden, but nice to hear you at least have junkyards ;)

    And yes, you can get lucky (Volvo front radiatorgrill and centre-speakergrill for 10euro!), but most times the US is cheaper than NL...
     
  7. valde3

    valde3 Senior Member

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    You just need to learn the good tactic and use good pliers with those hog-rings.

    Junkyards here work just like any part store. You go to counter and they check form the computer if they have the part. Or you can just check it online yourself before going there. Parts are already removed, cataloged, and pictured. Or now day’s junkyards do buy lots of parts from abroad as a bunch. That saves them a lot of work as the removal, cataloging and picturing are already done.
     
  8. VFerdman

    VFerdman Senior Member

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    Well, yesterday I only had time to install the heating pads into the seats, but not do the wiring. I took some pictures of the passenger seat work. It was pretty straight forward. I removed the seat from the car and brought it inside my shop and did most of the work on my workbench. There were a few hog rings to deal with and on the first seat I did (the passenger one) I undid more hog rings than I needed to since I was exploring my way into the upholstery.

    The back was fairly easy. I just undid three rings at the bottom and slid the fabric up about 2/3 of the way. Up to where it is attached to the foam by more rings and a steel wire. I did not undo those since the pad reached just up to that point after I cut about 1" off it. These pads you can cut to length. 1" off the top of the pad barely even cut into the actual heating element. There is about 3/4" of margin there.

    The bottom was a bit more involved since I needed to get the fabric off most of the cushion. In the center and on the sides of the bottom there are also a wires that hold the fabric to the foam with some rings. I undid all of those on the first seat, but only the center ones really needed to be undone. The side ones can be left alone since the pad is not wide enough to reach them. after getting pads in place I reassembled and it looks pretty good. Can not really tell anything happened in there.

    [​IMG]

    Edit: I tried to share photos from Google photos and they are not showing up, sorry. If anyone knows why not, let me know, please. Or suggest another way to insert photos here.
     
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  9. dolj

    dolj Senior Member

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    Use the Upload a file button:
    Upload a File Button.png

    The file inserts at the current cursor position. You can choose thumbnail or Full Image (per image or all images).
     
    SFO likes this.
  10. VFerdman

    VFerdman Senior Member

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    Let's try this for pictures.
     

    Attached Files:

  11. VFerdman

    VFerdman Senior Member

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    Thank you. That worked. But why doesn't a link work? That would save the PC host from uploading images that are already hosted elsewhere. There is a button for inserting links to images in the editing bar, but it does not seem to work. Strange...
     
  12. dolj

    dolj Senior Member

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    That is great in theory – until the 3rd party host changes its T&Cs or the account is closed or abandoned on the 3rd party site. At least if the pics are hosted on PC, posts still contain the pics.
     
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  13. R-P

    R-P Active Member

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    Thanks! Looks much simpler than the wiring embedded in the Volvo seat. Did you just unplug the airbag in the side of the seat?

    I could be mixing up the Volvo and the Prius, but I think I went through some trouble to NOT disconnect this when mounting my amplifier (mounted on the underside of the passengerseat-rails).



    Edit: when looking for a pic from my amp, I found a pic of the Volvo seat. It is actually NOT that different... It is also pads glued to the foam, but indeed some recessed parts that don't run wires, I just used them to run the purple wire, which is my fix for a wirebreak around the black charred foam. The wire break was in the side-pad, this is the drivers seat on a LHD, so it gets squashed every time you get into/out-off the car.

    [​IMG]
     
    #13 R-P, Nov 25, 2017
    Last edited: Nov 25, 2017
  14. VFerdman

    VFerdman Senior Member

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    Just finished the install, finally. It was in the 50s and I could work outside with my bare hands. I find that my bare hands do not work well when outside temps (in Fahrenheit) are lower than my age :)

    I installed the switches in the center console yesterday, but then ran out of daylight. Today I dealt with all the wiring. I picked up 12V from the big fuse box under the hood. I used a 14 gauge wire and soldered a lug onto one end and attached that under the 12V nut on the jumping terminal. Then I added an inline fuse (30A) very close to the box and ran the rest of the wire through the firewall grommet into the passenger compartment right above the brake pedal. then to the left side under the trim to about the middle of the front driver's seat and over to the center console. I took the driver's seat out to make things easier (had to unplug three connectors under the seat). I ran the 12V wire under the carpet to the center console, which I removed and exposed a steel box of some sort. I used that steel box for the ground connection by drilling s 1/8" hole and screwing in a self-tapping screw in it. I attached all the ground connections to that screw using lugs. I then wired up a relay that is controlled by a wire a spliced into the power plug in the center console. That plug is off when the car is off, so that makes sure that the seats will not stay on when the car is turned off. The relay when the car is on completes the 12V circuit and that feeds the heaters. It took some soldering and wiring, but it all works so far. I went for a little test drive and it was real toasty under my butt. My wife is going to be very happy, I think. This mod was mostly for her. Hopefully I did not screw up anything major in long term. I am concerned about the new 12V wire chaffing and touching the chassis somewhere, but I was careful to route it in a way to avoid that.

    I did not take any pictures today, sorry.
     
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  15. R-P

    R-P Active Member

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    Thank you very much for the update!

    General info, not specifically aimed at you:
    Just make sure you fuse ANY wire in the car according to its wire-size. There are tables to look up how much amperes a wire can carry*, then pick a fuse lower than this number and put a fuse between the pick-up-point (e.g. the battery or the fuse-box under the hood) and the rest of the wire. Keep this fuse as close to this pick-up point as possible. In caraudio this is determined to be 12", but I 'met' the guy who came up with this number online and he said he just thought that was a workable distance when on the plane to a carshow :ROFLMAO: I would keep it closer.

    The goal is that this fuse will always blow in case of an error somewhere before the wire gets so hot it will overheat and be a risk to you (burning) or your car (flaming ball of fire).

    Here you can convert wires between AWG and mm^2 (millimeters surface area).
    The reason I linked this is because I use the square mm^2 number via a rule-of-thumb to determine the maximum current.
    Your 14AWG or 14Ga is 2.08mm^2. multiply this number by 10 and you have an indication of current capablility: 2.08x10=20.8, or 20A.
    So other tables will tell you 30A is fine (though on the upper limit). I would limit it to just 20A and in case it is used under carpet or otherwise sealed off, I would use a safety margin of half, so use a fuse of 10A.
     
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  16. VFerdman

    VFerdman Senior Member

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    I used a 30A fuse on that wire, which is too high. The heaters draw about 6A per seat on high position, so I should really be okay with a 15A fuse. I used a heavy speaker wire I found. It may very well be 12 Gauge.

    Thanks for the explanation of the importance of fusing.