how does the 2003 heated seat switch work?

Discussion in 'KJ General Discussion' started by lbengr, Aug 8, 2020.

  1. lbengr

    lbengr New Member

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    Aug 8, 2020

    New to the forum. I needed a new work from home chair, so I decided to make my own. I went to the boneyard and found a clean 2003 Liberty leather power and heated passenger seat. I mounted it to the base of a shop chair, added a 110v - 12vdc power converter and figured out the wiring to make the power seat move. Reading this forum, I understand the heated seat module is actually mounted under the driver's seat, went back to the boneyard to pull the module to make the headed seat work, but it wasn't there, someone beat me to it. So now I'm trying to figure it out on my own. I pulled the 16142-kj_sm.pdf service manual, found the wiring harness from the passenger seat to the headed seat module has the following wire connections:
    - Violet/Lt Grn == Lo LED, grounding makes LED light
    - Violet/Black == Hi LED, grounding makes LED light
    - Pink/Black == temp sensor +
    - Tan/Dk Blue == temp sensor -
    - Tan/Lt Grn == Lo Button/Hi Button MUX

    I have the heated seat power connected, when pressing Hi/Lo, the seat heats, basically open loop and just keeps heating until I remove power. Pressing the Hi/Lo button doesn't turn it off, figured it probably wouldn't, but gave it a shot.

    What I'm having problems with is figuring out how the heated seat switch works... it's a MUX'd signal according to the service manual (8E-24...27), but it doesn't say what the signal is that is sent to the module when a button is depressed. I've watched it with an ohm meter and there's no real difference in reading between Hi/Lo button presses. Did the same with DC voltage and again, couldn't discern a difference between Hi/Lo. Does anyone know how the MUX'd switch / signal works?

    thanks for a constructive response!
  2. Big Al

    Big Al Let's get Cracken

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    Jul 26, 2020
    I used my 2003 heated seat by accident today.
    You press on the low to turn it on, then press again on the low to turn it off.
    Hope that helps you.