90 ZR-1 dash indicator reset - NCRS Discussion Boards

90 ZR-1 dash indicator reset

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  • Jerry G.
    Extremely Frequent Poster
    • March 31, 1985
    • 1022

    90 ZR-1 dash indicator reset

    A buddy of mine is getting ready to start up his 90 ZR-1. He had to jump the battery to get it started. It's running fine ,however, the process of jumping the batterey causes the "inflatable restraint" indicator to come on and stay on. in the past he took it to his local chevy dealer and they reset it. This time the dealer says nobody there knows how to do this any more and they don't have the ability. Does anybody on this board know how to reset this indicator on a 90 corvette?
  • Tom H.
    Extremely Frequent Poster
    • November 30, 1993
    • 3440

    #2
    Re: 90 ZR-1 dash indicator reset

    I remember seeing that light on many ZR1's. It was usually either the DERM module, a discriminator or a bad ground that caused the light to illuminate. I don't recall a reset procedure. Might have been one, but I don't remember it. If you can reset it, the light will most likely re appear until the issue is resolved.

    Here is an article I pulled from the Corvette forum. Not sure if this method works, but it seems several members used this technique.

    How to correctly and
    inexpensively correct the 'Inf Rest' light on 1990 Corvettes.



    The 90 is infamous for this light staying on. It seems that
    there are two sensors, one on the frame underneath the battery box, and
    one underneath the windshield washer container. Both bolt directly to the
    frame. These little electronic wizards detect a crash via vibration in the
    frame, and then set off the air bag.


    The problem is two fold.
    First, their location promotes getting water on them. Secondly, the water
    causes a corrosion problem between the sensor and the frame. These little
    wizards are so sensitive to corrosion, 1/2 of one ohm of resistance that
    developes between it and the frame will send a fault light code to the
    computer, and trigger the trouble light. Most of the time, the air bags
    are still functional, just the light is on.


    But, on to fixing
    the problem...


    First, let's check the codes in your computer
    to make sure this is the problem. Using a long jumper wire, jumper pin # K
    on the computer link connector to ground, like the seat frame. Pin K is
    the fouth slot from the left on the bottom row, or third from the right.
    (The connector is under the drivers side dash). Turn on the ignition, but
    don't start the car. Via flashing engine light, you will be able to read
    the codes in your computer. It will first flash a code 12 three times. The
    light will flash like morse code, a long lit bulb, followed by two short
    lit bulbs will be a 12. Once the three code 12's flash, then you will
    have another code, likely it will be a 25 or 26, but could also be a 15 or
    16. ( , Mine (Jay) was a code 16, Indicating right side sensor) If it is
    not one of these, you have a different problem, so let me know if your's
    is not one of these. Code 26 is most common, right front sensor fault.



    Assuming you have a 15, 16, 25, 26 code, you will be following
    the service bulletin #90-436-9J. To fix, you have to unhook the battery.
    Next, remove the side panel and inner fender well cover from the front
    tires. (Note, I also had to remove the tire to get to the bottom 2 torx
    screws) Then you can unbolt the sensors. Next sand the frame and back of
    the sensors with sandpaper, and then install di-electric grease (I found
    permatex tune-up,
    di-elecrical grease at Pep Boys) on the back of the
    sensor, then re-install it.

    After this is done, you can then reset
    the computer. Now this is where the dealers have all of the problems.
    Since it is very difficult to reset, they usually replace the sensors with
    new ones, so they dont have to go through this. But if you can accomplish
    this, it will save you bunches of green paper!!!


    Taking a
    jumper wire hooked to terminal K, ground it to the seat frame, and count
    one thousand one. one thousand two, one thousand three. Then unhook it
    from ground, count one thousand one, one thousand two, one thousand three.
    Then reground it once more, and count one thousand one, one thousand two,
    one thousand three. The code will disappear, leaving only a code 12 if you
    are successful. If not, retry it again and again. A friend of mine did it
    10 times before it was successful. But, think of the money you would have
    to pay a mechanic to do THIS!!! ( , this is where I had the most
    trouble, until I got an email from Dan's friend and late-model guru, Ed.



    Here is the secret....With the ignition off. Place the jumper
    wire in the K terminal and ground it to the seat frame...Switch the
    ignition on and AS SOON as the light begins to flash, remove the jumper
    from the frame and count 1001,1002,1003, Then reground it and hopefully
    you will only see code 12's flashing. I spent an hour yesterday doing it
    wrong and tonight I got it the first try using Ed's method. Anyway, on
    with Dan's instructions) The A/C condensor is what drops water on this
    sensor, and causes the problem.


    In 91 they used di-electric
    grease, and the problem was fixed. As a precautionary note, do not use a
    volt ohm meter to do any troubleshooting with this system. The battery in
    the ohm meter will set off the air bag system. This is how mechanics get
    really in deep s@#* with their boss! As long as you can refrain from
    using a meter, you will be ok.


    Tom Hendricks
    Proud Member NCRS #23758
    NCM Founding Member # 1143
    Corvette Department Manager and
    Specialist for 27 years at BUDS Chevrolet.

    Comment

    • James W.
      Expired
      • November 30, 1986
      • 278

      #3
      Re: 90 ZR-1 dash indicator reset

      Try this link. http://corvettemechanic.com/forum/c4...al-issues.html

      This guy is really good on technical answers. Seems like a straight shooter.

      Good luck
      Jim

      Comment

      • Jerry G.
        Extremely Frequent Poster
        • March 31, 1985
        • 1022

        #4
        Re: 90 ZR-1 dash indicator reset

        Thanks guys thats what he needed. As complicated as this is I was expecting dressing in feathers and dacing around the car counter clock wise

        Comment

        • John H.
          Beyond Control Poster
          • November 30, 1997
          • 16513

          #5
          Re: 90 ZR-1 dash indicator reset

          Originally posted by Jerry Gollnick (8575)
          Thanks guys thats what he needed. As complicated as this is I was expecting dressing in feathers and dacing around the car counter clock wise
          Jerry -

          That only works if you're wearing a hooded robe and throwing burning chicken bones into a smoking pit.

          Comment

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